Some of Apple's HTML 5 demos use an html4 loose doctype:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
What reasons could they have for not using the HTML5 doctype?:
<!DOCTYPE html>
EDIT: I am really looking for technical answers here not political, perhaps I should of reworded this question to "What could be gained from using an HTML4 doctype when using HTML5?" - Apologies for the confusion.
Because behind that Fortune 500 company, the marketing veneer and all that imposing technical knowledge/reputation is just a group of people who sometimes make mistakes. Same as you and me.
Consider it a bug and report it.
Because those demos are just marketing. They are not built using best practice and they do not really show much HTML5 at all.
In fact, they even block Google Chrome 5 and suggest that you'd upgrade to Safari 4. LOL!
Maybe they use some tags that have been dropped in HTML5, and don’t use any of the new tags in HTML5? So they leave in an HTML 4 doctype to make the pages easier to validate?
I can’t think of a good reason.