As an end result, maybe. But it also means that you get specific feedback on how to properly author it correctly and fix it before pushing it live.
IDK, I lived through that whole era, and I’d attribute it more to the fact that HTML is easy enough to author in any text editor by complete novices. XHTML demands a hell of a lot more knowledge of how XML works, and what is valid (and, more keystrokes). The barrier to entry for XHTML is much, much, higher.
I don’t know if it’s “most people,” but I agree, there is no excuse for frameworks producing sloppy output - that being said, XHTML is a bit more chatty than HTML(5), so there is some minor benefit to not using the less verbose standard.