Google doesn't particularly have a fragmentation issue, really...
Look at Windows. Intel/AMD/VIA, nVidia/ATI/Matrox/S3, WD/Seagate/Maxtor/, etc etc. for the most part all working well.
Dell, Gateway, HP, Lenovo, all get their OS updates direct from Microsoft, can have Windows loaded fresh on any system.
Google's Android problem is they handed control back to carriers. Carriers and manufacturers. Modifications and addin crapware that break ability to update.
They've gotta shove a boot up the Carriers' ass.