Bottom brackets are an example where we're coming back to sanity. The pressfit junk they pushed on us was for ease of manufacturing and low cost. Consumers realized they were worse, and they started to avoid those. The manufacturers have caught on and started putting threaded BBs back in, as they ought to.
We've mostly got a set of semi-reasonable standards. In the MTB world at least, 148 rear hub width is almost ubiquitous, and 15mm front axles with boost spacing are effectively it outside of downhill applications. 6 bolt rotors of various sizes are essentially standard.
The majority of the pain is where the big manufacturers (SRAM and Shimano) are battling it out: hub and chain/shifting standards. That is admittedly painful right now, but you can chalk most that up to corporate greed.
All in all, I don't get the concern here. With a little bit of consideration of compatibility in a couple areas you can mix and match brands pretty easily on most of the bike.
From what I've seen said by bike experts on YouTube, pressfit is actually superior, because it saves weight, and is (maybe) still used on top-end racing bikes for this reason. The problem with pressfit is that it requires very precise manufacturing, and apparently most mfgrs just can't make a proper round hole in carbon fiber. Threaded BBs are more practical because they allow for sloppier manufacturing tolerances.
Of course, threaded is better for end users who want to do their own repairs, since it doesn't require special press tools like pressfit does.
The issue (according to the YouTube experts) is that for mass-market bikes, the manufacturers have somewhat poor quality control and manufacturing tolerances (as far as drilling holes apparently). For a press-fit BB (bottom bracket), you need an extremely round hole, accurately sized for the BB to press into (hence the name).
For a threaded BB, this isn't an issue, because those aren't pressed in. Those have an aluminum threaded part that's bonded into the hole; the hole doesn't have to be super accurate, just good enough for the aluminum part to fit into properly and get glued in. The aluminum part has the threads and perfectly fits the BB, and since it's machined out of aluminum at some other factory, doesn't have the problems with tolerances that the CF parts have apparently.
I will admit I do prefer a threaded BB, but I also think it’s an overstated issue.
Then again, my frame is steel and I run a pretty high end Wheels Mfg BB. Maybe I’m insulated by that.
There's lots of other ways to address PF issues, I think it's just that consumers know about the issues and prefer to avoid them if possible.
I bought a -cheap- beater for a family member a few weeks ago for the grand sum of $80. It is an excellent bike by a prime brand manufacturer, it needed a little bit of work (roller brake service, one new spoke, some grease and a new rear light) and it's as good as new. I fully expect it to outlive me, and probably everybody else in this house if it is taken care of as well. I regularly see bikes from the 60's around here that are still in very good shape.
The bike industry lives by: theft, bike accidents, kids growing up (kids are really rough on bikes) and cracks in frames. Everything else is fixable if the bike is of a reputable brand.
Crap bikes not so much those have the weirdest parts.
I'm nowhere near an expert but I think most small (or steel) bike brands never moved off english threaded bottom brackets so I think that's mostly a major manufacturer issue. The brakes are frame dependent but calpier and cantilever arms are fairly simple/available or flatmount if discs (ignoring that Shimano just kind of decided they didn't like post mount). Finally, if you're comfortable with (ratcheted) friction shifting then most drivetrain compatibility issues are covered.
The components themselves tend to be pricier since they're targeting a niche market but there are people serving it.
I love how much people hack this stuff to overcome corporate shenanigans!
(Seriously, the complete bikes they sold are literally more expensive than any car I've ever bought. Not that I wouldn't like one, they're even roughly the style of bike I like, but I wouldn't use one enough to justify it. Their parts though, they're heirloom quality solid performance.)
There's a ton of custom and semi custom manufacturers out there of parts and frames, some of which are even affordable. A quick perusal of the Radavist will give pointers galore. Some of them even do production runs to make frame prices under 2k.
Personally, I like the look of the Crust Lightning bolt, but it's seriously pricey to import to the EU, so maybe something more like the Brother Mr. Wooden is next in line for me.
If I'm going to pick a fancy niche frame I don't want to afford I'd opt for a Jones LWB space frame. I'm actually a recumbent rider so the more likely expensive cycling purchase would be a velomobile.