First off. The current web works. Almost all sites that you want to be on render decently well in IE, Safari, Opera, and Firefox. It's usable and being used.
Now there's room for improvement, heck I've cursed while trying to use CSS over and over. Looks perfect in one browsers, hideous in another. And then it'll just not behave as my references say it will. gah. But it does work eventually just with frustration.
Anyhow back to XHTML vs HTML.
XHTML is the proper thoughts and theory, but it just doesn't make sense in practice in many ways. Whereas HTML works great in practice. This is why the browsers aren't supporting XHTML 2.
Lastly there's no reason to make pages break if their formatting is a little off. That's dumb, the Internet is so much about freedom of information including the freedom to post it. Of course if they don't know what they are doing they should lean towards stuff like Google pages. But I've made my dumb mistakes and I'm glad my pages don't just break because I forgot to close my last div tag.