and I'm saying: if THAT is what you call "works just fine", then the whole concept of a hybrid document is broken and it's great that we've abandoned it.
So really, you have no argument, except for a distaste of XHTML. Gotcha.
It seems better to mix that with SVG than HTML5, since SVG happens to also be XML based. Otherwise you have a impedance mismatch leading to some weird corner cases.
my argument is that you might be able to make it work through a lot of effort but you can't actually use it in the real world so it's worse than worthless.
You are saying that XML hybrid document stuff doesn't work in "real" browsers? Do IE, Firefox, Safari, Chrome and Opera not count as "real"?