If history has taught us anything, it's that Google is happy to willfully ignore, rewrite, and use their market dominance to snuff out any existing standards if they see a way to seize control and make money off something.
Absolutely, but in the context of IMAP, it's already a mess of special cases. Gmail having a weirdness, an extension or two changes basically nothing. Not to mention the fact that what they offer over the web is more flexible than what IMAP usually allows, it simply does not and can not map directly to IMAP.
It's really dumb that one message has* to exist in only one location for example, labels are so much better.