I think accessibility is usually completely forgotten about (either implicitly or explicitly dismissed beforehand because of issues like cost) in most software development projects. Unless companies (or individual developers, more likely) already have experience with either people with disabilities or with writing software with disabilities of users in mind.
As a developer I at least try to do keyboard shortcuts correctly in software I work on (because that's something I can easily dog-food myself, since I try to keep hands-on-keyboard as much as possible). Apart from that it depends on whether there are requirements about accessibility.
I do think this kind of thing is part of "programming taxes", i.e. things that you as a developer should always be doing, but...
I am only aware of this - at least more than the average developer, I think - because I have once wrote software for a software magazine on floppy disk, or Flagazine. This was in PowerBasic 3.2, grown out of BASIC sources in a magazine, making these sources available by BBS and disk, eventually growing a menu around the little applications to easily start them, etc.
One of our primary users (and later members of the editorial staff) was blind and was appalled when we switched from text mode to an EGA mouse driven menu, as his TSR screenreader software couldn't do anything with graphics. It turned out that his speech synthesizer simply accepted text from a COM port. It had a small (8K I think?) buffer that would be instantly cleared on reception of (I think) an ASCII 1 character. And that was it.
So we made the graphical menu (and most other programs on the Flagazine) completely keyboard accessable at all times and in the graphical programs we use a small library I wrote to send ASCII text to a configured COM port. This had small utility methods like ClearBuffer()
. With this, and the convention of speaking possible menu actions when pressing the space bar, made all of this software accessable to our blind users.
I even adapted a terminal application for my HP48 calculator (adding a clear buffer/screen on ASCII 1) so I could use that to emulate a speech synthesizer. I would then test all of our software in each Flagazine by attaching my HP48 with the emulator running, turning off my computer monitor and trying if I could use all the software without seeing anything.
Those were the days, about 12 years ago... ;-)