I sometimes worry that this focus on accessibility testing and the industry around it makes folks think this is some monumental undertaking that they can't hope

I sometimes worry that this focus on accessibility testing and the industry around it makes folks think this is some monumental undertaking that they can't hope to approach themselves. But a lot of these issues are glaringly obvious (e.g. "this UI element has no label so I can't identify it"). The visual equivalent would be shipping your app with transparent text labels or a 2 pixel font height. Any developer can test their software with a screen reader for free. If it's not usable with a screen reader, it won't be usable to screen reader users. The problem is that almost nobody who isn't Blind will do this, or even consider doing it. They'll effectively build an entire UI flow without running through it even once. If you're lucky, they'll work at a company that has some policies and checklists for accessibility and they'll follow that. If you're really lucky, they'll pay to have someone else do accessibility QA. But even just testing it yourself the way it's going to be used would be a huge step up.