E. Allen Emerson, later Turing Award recipient, comes knocking at the door of the Unix cave[1] and demands to know why we changed all the fonts and made his papers look different. No one had changed the fonts---the department had replaced the printers. CMR is wildly different at 600dpi from 300dpi.
Personally, I never really liked Computer Modern mostly because the variation in stroke widths was too great. The thin strokes just look spindly. Personally, I much prefer Computer Concrete, which looks horrible in the samples on the web page.
[1] Where UTCS' Unix sysadmins live.
This is the initial reason. It persists because it is part of the shorthand filmmakers use to estimate time from text. A page of screenplay translates to about a minute of screen time. That conversion is deeply ingrained in Hollywood. Everyone will look at the page count of a screenplay and make assumptions about the running time of the resulting film.
If you change the font metrics, that conversion breaks and it would confuse the hell out of everyone. And if different screenplays (or different drafts of the same one) use different metrics then you lose the ability to compare their length just using page counts.
It's important to remember that screenplays are real physical working artifacts. In the production of a film, people will be carrying around dog-eared copies of it. The director will say things like, "We're going to try to get through three pages today." Pages are a real concept, not just an arbitrary subdivision of a continuous string of text.
Also the font is part of film culture at this point. Using a different font would convey that you are an outsider or don't care about the norms and history of cinema. It's exactly how when you see a page set in Computer Modern you think, "Ah, this is a real CS paper." A screenplay not set in Courier would look like a fraud.
If it makes you feel better, John August has a slightly more modern font that preserves the exact metrics of 12 point Courier:
Knuth designed in a "blacken" factor and gave instructions how to tune it to your specific printer.
Because the correct amount is dependent on your printer and its printing technology. Ink tends to blur a bit, for example.
There are font files around that try to make CM a bit more correct on typical printers today, but most people don't know about it and are using some bad default CM.
Amusingly enough, this is basically "The Renaissance" done in a short time; just as they perceived the "Greek" style as bare marble statues and buildings which never actually existed.
https://youtu.be/pU4jnSVfZsI?t=188
(left side at the time marker is the original Gamegear screen, right is a mod with a modern screen)
Oh, found one of a Nomad with the original screen:
https://www.youtube.com/watch?v=9j0mXNb6YPk
Similar. A little less washed-out, but still not what we think of when we think of the precision of a modern LCD.
As I recall, LCD PC monitors until some time into, I dunno, maybe '05 or so, were regarded as almost always worse than CRT monitors in practically every way[0], including picture quality. Better than a typical consumer tube TV, maybe, but even some of those produced a crisper picture than a lot of LCDs, especially tiny low-power ones like that (the Sony Wega comes to mind)
[EDIT] [0] Practically every way except size & weight, I mean, obviously, and despite crushing CRTs on that front, were pretty unpopular due to being so much worse otherwise.
But there's also an annoyingly performative aspect to it, at least in Economics. Using a recognisable LaTeX font carries an implicit "look at me: I'm smart and technical enough to use LaTeX".
One result of this is that almost every Economics presentation you see is done with Beamer; which lends itself to dense text, bullet points and equations; which are almost never the best way to present your work.
I don't think that has anything to do with Beamer. That's how economists present for some horrible reason. When I was on the job market about 20 years ago, the overhead projector was the only tool universally available for presentations, and I had a couple people comment that my work would be discounted by some because it was too easy to understand. That was back when I mistakenly thought the point of the presentation was to explain my research.
I think that’s what drove the defaults of PowerPoint, with its white text on a dark blue background (see https://www.edwardtufte.com/bboard/q-and-a-fetch-msg?msg_id=... for arguments as to why that’s good for slide projections. I think it also minimizes contrast differences between typical “medical conference” photo and text slides. That’s important in a darkened room , which they had to use because projectors weren’t bright enough yet.
Making things easier on the other hand is liberating, but sadly comes at a cost (people might start thinking you only do trivial work)
Haha, either they discount it because they understood it, or they respect it but don't know it. In either case, it's like they never saw the presentation.
I think that Computer Modern is OK for print; it is not so good for screen. (However, it does have better kerning than some screen fonts.)
So it’s fair to say that CM is a tech demo, not a professionally designed font.
Font designer Jonathan Hoefler has commented on Metafont: “Knuth's idea that letters start with skeletal forms is flawed.” When the fundamental design premise is wrong, you get something like Computer Modern.
While it's true that Knuth is a computer scientist rather than a typographer, he has worked pretty closely with typographers. And in creating CM, he relied heavily on pre-existing (and professionally designed) Monotype fonts as a model. (See for example https://www.myfonts.com/fonts/mti/monotype-modern, which looks quite reminiscent of CM.)
Computer Modern is not to many people's taste today, partly because it doesn't reproduce all that well at low resolutions, but also, I think, because it is an older style that is now out of fashion and not commonly seen.
(The term "Modern" for this type of design dates from the 1800s -- see https://www.toptal.com/designers/typography/typeface-classif... -- so it's hardly surprising that "modern" faces like Bodoni or Monotype Modern or CM feel rather old-fashioned today!)
This is a critique of Metafont, not Computer Modern. And interestingly, Knuth et al eventually reached the same conclusion; as I recall, most letters in Computer Modern are drawn as outlines and then filled in (instead of being drawn in a few strokes with a broader pen).
I think Hoefler phrased his comment well; the idea is flawed, not necessarily wrong outright. Letterforms derive from historical constructions: the uppercase roman letters from Roman square capitals, which were carved; lowercase from humanist miniscules (from carolingian miniscules), written by pen; &c. So in some sense, some letters do start with skeletal forms, but: when letters were adapted to print, the punches (the "master copies") for letters were made by engraving and by using counterpunches (reusable tools that create particular shapes of negative space in the letter). And that's where metal (and digital) type comes from; pens and styli are more distant ancestors.
[I'd highly recommend the book Counterpunch by Fred Smeijers on this topic!]
[Also, it's fun to look at some of the Arrighi italics from the early 16th century. They are astonishingly modern – compare it to, say, a heavier weight of Minion italic, one of the most popular typefaces used in books today!]
Anyway, on to Computer Modern. It's not my favorite Scotch roman, but take a look at engineering and mathematics books from the 1940s and 1950s for comparison. I have several books from the McGraw-Hill Electrical and Electronic Engineering Series, and they're really, really lovely, and the type is eminently readable on the printed page; here's a (somewhat poor) scan of one of them:
https://archive.org/details/Vacuum_Tube_and_Semiconductor_El...
In all cases, Knuth is not a font designer so it's not shocking that the font isn't as nice as something like Arno.