If Google had designed (? or something?) Android so that updating the base OS was something that could be pushed direct from Google instead of from each manufacturer's bollixed version of the system, there'd be no problem for any of us.
That may seem obvious now, but it's far from clear that Android would have succeeded the way it has if OEMs hadn't been allowed to differentiate their versions. That was (and is) something that's important to them, and they may well have decided that they wanted to do their own thing instead if Google hadn't given them the degree of control they wanted. Or maybe they'd have adopted Windows, since while it wouldn't allow them to customize it would have had the advantage of being from the then-biggest OS maker around.
It seems very likely that the ability of OEMs to customize was a core component of what made the Android ecosystem successful.
Also, keep in mind that the only way Google could really have kept OEMs from modifying Android however they like would have been to keep it closed. Personally, I'm glad that Google made the choices it did, not because I'm a Google employee working on Android (though I am), but because I've been an open source and free software advocate since before Google even existed. Android is far from perfect, and devices aren't as open as I would like, but I think the mobile software world is much better than it would have been without a F/LOSS mobile OS.