I hear your argument & it's valid but it's important to not wholly discount image & marketing when choosing a solution, as they also affect how widely used a product is, for better or worse. Apps are "cooler," some people will be more inclined to use it as an app. Again, this isn't a really meaningful reason but it's a real factor and bears consideration. I'm not sure if bookmarking to homescreen is a common workflow for many people.

My point is that there's a trade off (I tend to suspect people would use a mobile site less; you have to find it each time etc.) and if you determine that product X would be less accessible, but used by more people, if you implement it using technology Y, it's not unreasonable to accept that compromise.

Lest I come of as a grumpy gus that doesn't care about accessibility, I'll link to this PR https://github.com/tastejs/todomvc/pull/37 which hopefully illustrates that I do care about accessibility, I just recognize that there are other factors when choosing a solution as well and not all will be perfectly accessible, for better or worse.