A curious thing is that lots of accessibility improvements tend to be good for all users. Getting rid of crazy Javascript things which screen readers can’t understand makes it less likely that your website is buggy and fails for some regular users. Using simpler HTML (ie with actual links and forms) decreases the chance that it fails in some of the weird browser setups that some people will have (eg old phones or computers or weird devices like smart TVs or kindles).
Making your app/site simpler and easy to use for the large number of people with very low computer skills can often improve things for those people with good computer skills too.
Similarly if your site/app is made accessible to the surprisingly large proportion of the population with low literacy then it will also work better and faster for those people with good literacy too.
