There's no shortage of stories about Android's fragmentation problem, which usually refers to how far behind the manufacturers are when it comes to upgrading their own devices. It usually takes at least 6 months for them to do it, and by then Google has already come out with a new version of Android.
Chrome and Chromium are the role models for what Android should've been as an open source project. Chromium is the fully open source version, while Chrome is the version that only Google is allowed to touch and control. But because Google themselves have promoted Chrome from day one, 99% or more of the users prefer Chrome over Chromium. That means that if some manufacturers want to put Chrome or Chromium on their devices, they will certainly choose Chrome, because that's what their users know and want.
This is how Android should've worked from the beginning. Use a version that is completely open source (just like Chromium), but one that is promoted by Google to both users and manufacturers (such as Chrome), and then they wouldn't have had any of the fragmentation and upgrading problems. All the upgrades would've come from Google, and possibly a lot more often, too.
Sundar Pichai as leader of the Chrome and ChromeOS projects, has decided that they can and will upgrade them every 6 weeks. That's amazing when you think about it, and we can only dream Android could one day be upgraded this easily and this often. But according to analysts, this may be one of the reasons why Sundar Pichai is taking over Android.
Don't expect any major breakthroughs in how Android is going to be upgraded anytime soon, though. As we've learned from the deal with Motorola, it can take years to turn things around, and start implementing the new plans. I do hope they have something prepared for Android 6.0, though, which I believe will be the first 64-bit Android version, next year.
The 64 bit version won't be necessary to kick-start the "ending of fragmentation" program, but it would be a great opportunity to start there, as the 64 bit version of Android will be somewhat different anyway, and OEM's will have to decide to use that instead of the 32 bit one. So if the 64 bit OS incorporates all the infrastructure for a much cleaner upgrade program, handled by Google themselves, then it would be that much easier to get them to agree to this upgrade program.
The 64 bit Android could be where Android gets a clean start, also on the new ARMv8 architecture, that is a cleaner architecture than ARMv7, too. This could be Google's opportunity to start things all over again, and also decide on a unified driver model for all manufacturers, so it makes upgrading that much easier. It could even make installing a master Android ROM on any ARMv8 device, just like you can install Windows on any PC. That's a future I'd really like to see happen, and I can only hope Google has the same thoughts, too, and they plan on implementing them as soon as possible.