Android has become somewhat infamous for slow (almost unbearably so) updates for users of pretty much any non-Nexus device. In fact, when Jelly Bean was announced earlier today, the first thought on some users' minds was that their handsets haven't even tasted Ice Cream Sandwich yet.
Google is well aware of this issue, though - last year, it made an attempt (albeit a feeble one) to solve the problem with the Android Alliance. I think we all know how that turned out.
This year's I/O saw a related announcement: that of the Android PDK, or the Platform Development Kit. In short, it's a set of tools which will aid manufacturers in porting new versions of Android to their devices and which will be released to said manufacturers a few months before the public launch of each major Android update.