Don't normally comment online as I find it a lot of work (it's taken me about 5 hours to put together this pretty badly written response), but while there's a GTK dev here on topic I don't want to miss the opportunity.
> There are way more types of impairments than visually impaired.
Thankfully I have perfect eyesight, however I am very dyslexic. I have problems with spelling, but Google's search spell checker and voice recognition have made huge differences to me in that respect over the last year or two.
But relevant to GTK - I have a terrible short term memory. A goldfish like short term memory. I can barely remember a sentence when switching between windows, 5 numbers is a challenge (no distractions please) and remembering how another programmer abbreviated a variable's name is a huge distraction.
I can't organise IRL or digitally. When I'm programming terminal windows just keep piling up, because I can't remember what terminals are doing what (is that sitting at a prompt or is it watching a folder with inotify?). I could click through the open terminals and disrupt my chain of thought and forget what I'm doing or I could just open another terminal, keep working and do a closing session every so often.
So onto how GTK is making my life harder: by making widgets more accessible to people with impaired vision/touch screens they've made them bigger. I can now fit less on screen and I have to remember more. I have to move between windows more and I have to scroll more. This really is making my life much harder, I'm honestly getting lost on my desktop because I can't remember shit and I'm constantly having to switch windows - because there just isn't room any more for two side by side windows on 720p.
And it really never used to be this way. Compare Gnome Terminal with xterm. Yes gnome terminal is better, for instance you can turn off bold fonts (Myself and many other dyslexics have problems with bold and especially italics) and have a nice GUI for changing the settings. But it's visually huge. I'm pretty sure (unfortunately not checked at all, I use XFCE - because it's smaller on screen) with the default font settings you've got just about enough space to tile 120 columns of Gedit and a 80 columns of Gnome Terminal - but not something you'd actually write code with, by the time you've got Sublime's side bar open you're going to have to shrink the fonts. And find a window manager theme with smaller borders. And find a reduced size widget theme (these often don't shrink out much whitespace). And after that somehow you'll still feel cramped, maybe it's because everything has been unnaturally shrunk.
And, really ranting now, the web is the same, I'm starting to quite regularly zoom out on websites to make them more navigable, I'm getting lost scrolling between the massive headings and huge white spaces. I can't find the damn menu buttons and by the time I've found them I've forgotten why I wanted them and have to mentally backtrack (What am I doing? Why? So why was I reading this? What was the bit that sparked something? Oh yeah! Right, back to the menu! Where did that menu go again?...).
Going to the terminal example again if I want to tile my XFCE Terminal and a Digital Ocean tutorial I've to zoom Digital Ocean to 90%. And Digital Ocean are efficient with screen space.
I'm currently using a 720p 13" laptop display and I think my next laptop is going to have to have a 1080p screen, just so I can fit whatever I'm working on. I'll then have to override the DPI settings of course and generally have a broken display setup. I'm looking to buy hardware and run a nonstandard setup to solve the accessibility problems that GTK has introduced for me when solving accessibility problems.
As an analogy to the situation (on bad days) I feel it's like GTK/Gnome is running around shouting "EVERYTHING MUST HAVE WHEEL CHAIR RAMPS! NO STAIRS! ACCESSIBILITY HAS SPOKEN!" ignoring that sloped surfaces can be difficult/painful for those with hypermobility syndrome. And when it's brought up "I'm able bodied but my knees are getting sore" (AKA "your widgets are too big I'm clicking around too much") the response is that it's accessibility and wanting something different is denying wheel chair users. But this response is missing that an able bodied person is having problems (they're being annoyed by it because it's causing them difficulty) and if an able bodied person is having problems then there is almost certainly someone less able who is having even greater problems.
As in able bodied people are complaining your widgets are too big because they're finding they have a higher cognitive load because they're having to switch windows more often. The reduction in general accessibility (higher cognitive load) is traded to enable specific use cases and it's considered ok. In testing you able bodied people say "this is barely harder" and your specific use case say "this is great". But what's missing that there are other people with other disabilities you never tested - we don't speak out because there's not many of us and frankly it's not very easy, both to speak out and to make a meaningful contribution to something as complex as UI ergonomics.
Basically what I'm saying is, yes it is good to have options for disabled users. But forcing the default is not a good idea and you might find you're causing problems. The default route into buildings with access ramps is still normally a set of stairs.
For example I could request that bold and italic fonts not be used anywhere in a UI, for me this would be great, but for able bodied users this would be a step backwards and reduce accessibility (the UI can't highlight important text for instance). Able users would complain, and it would be a mild "oh I liked it when the top command put the total memory in bold, it made it pop out a bit" to which GTK would correctly say "but dyslexics find this approach much easier" but this conversation misses that there is another category of people with poor eyesight who find the bold emphasis really helps them find the important details in the UI. But because GTK has made removing bold and italic default (in the name of accessibility) the user with poor eyesight has no options to turn that back on, and the community is already galvanised against allowing bold, because they did a UI study and it helped dyslexics.
> Count yourself lucky that you don't have an impairment (right now).
Worst of all is if the "but dyslexics find this much easier" statement has accusatory undertones of ableism (Despite my quote I don't feel audidude has done this). That might lead to the poor eyesight user to agonizingly craft a response over 5 hours that tries not to offend anyone in the galvanised community, because they don't have dyslexia and don't understand the difficulties faced, maybe they really are being ableist. Alternatively, and much more likely, they'll just keep quiet and GTK will carry on oblivious, making life worse for them.
Now I have got to thank GTK for being really good with having highlightable text in dialog boxes so I can copy and paste into Google. Also after spending a lot of my childhood in Learning Support classes I have to thank GTK for all the hard work they're putting into accessibility, it isn't sexy, it annoys people but it's damn important (even when I think it's going wrong and sometimes makes me wish I worked in construction).