In web apps, you can short-circuit this “there’s no business case” nonsense a bit by building your components using the accessibility attributes as the hooks between HTML, JS & CSS. E.G. rather than adding classes for everything you want JS and CSS to act on, instead hook onto the attributes role, aria-*, hidden and so on. If you do it as habit, it takes only a little bit longer to think about or type than attaching a class name, but helps you use the browser’s built-in accessibility support “for free”. If you work this way, you don’t even need to tell management what you’re doing.

I accept that this is easier on smaller, or new projects.

100% agree. I've noticed this as well. A lot of the time, the best objective-sounding argument for something I want is "it's necessary for accessibility", even though _I_ want it for reasons which would've been ignored. And a whole lot of the settings I rely on to make my computing devices comfortable are hidden under "accessibility" menus in settings screens.

There are even cases where the strongest argument for something to have a web version in addition to an Android/iOS app is accessibility. You can make some really interesting and specialized input hardware for Windows PCs which has no chance of working on an iPad, so there are people whose disabilities makes web apps way easier to use than any Android/iOS app. And if there exists a web app, power users can use the service from their comfortable desktop setup rather than from the tiny screen on their phone.

Accessibility is the most effective argument against the "one-size-fits-all" "it works for 90% of users" thinking that's otherwise so pervasive.

One of the first things I do on a new Mac is to enable three finger drag. A couple of years ago this option moved fron trackpad settings to accessibility options.

That’s when I understood that I had a disability.

yea when i was using windows a few years back i got some great mileage out of autohotkey + microsoft's accessibility access. (acc.ahk is the script someone make that interfaces with it if anyone is interested)

one good example was being able to control spotify. it doesn't work with the current redesign i don't think, but i used to be able to heart a song, show the current track name and artist in a tooltip, or list all the songs in your friends tab. lots of handy stuff like that and it all worked even when the spotify window was in the background