Yes, unfortunately that's exactly what I'm saying. In a perfect world, every app would be fully accessible, colorblind-friendly, work offline, etc etc. But in reality, all of those things cost money, and sometimes the cost outweighs the benefits. To give an extreme example, if my app has 1 million users, but only one is blind, do you expect me to spend (potentially significant) development resources on that single user?

You have to do that cost-benefit analysis based on how important those things are to your business—for instance, screen reader support is an absolute necessity for the public sector and certain information-heavy apps, but probably not as important for visual tools.

It's absolutely ridiculous how some content based websites require several MB of js to function. And the devs say this is because it is 'easier' to write such apps. And if the thought of optimization even comes to their minds, its just adding another layer on top of this madness to manage the layers below, or saying its too hard. Of course it is hard if you start with an overcomplex solution in the first place and try to trim away stuff from it. How hard exactly is it to write some plain html and css, with js doing some optional improvements? Most problems of web development are self inflicted.

I was talking to someone once about how ridiculously bloated Imgur is and that I had to use Imgoat because of the slow internet I was experiencing then. Of course they were trying to make all kinds of excuses like imgur not having servers nearby etc. But of course the really simple fact couldn't get to their heads that Imgur downloads like what 2-3 MB maybe even more of crap minus the actual image whereas Imgoat is something like 500 KB. No amount of network optimizations and caches etc are going to get over this fact. And also, such optimizations are over and above the page download size improvements anyways. If Imgoat used such techniques it'd be even faster. Most importantly: both sites have the exact same and simple core function, yet one site is so many times more bloated than the other. I will let you derive your own conclusions as to what this means.

And imgur also has the typical horrendous js misuses such as scrollbar hijacking that makes absolutely no sense etc.

There is nothing limiting a disabled person’s browser from executing JavaScript, screen readers are generally not concerned with how an HTML element was created (server side or client side), but just read what’s on the page.