Often, HTML is not hand-crafted by developers but created by content authors in WYSIWYGs or generated from markdown. Of course developers could find ways to for

Often, HTML is not hand-crafted by developers but created by content authors in WYSIWYGs or generated from markdown. Of course developers could find ways to force content authors to write accessible content, but most content needs to be cheap, so people will always find ways to take shortcuts. I don't want to say that modern JS frameworks aren't problematic, but I think they might only account for a small part of these bad numbers.