Android Police gives us A Definitive History of Android Version Adoption (via Daring Fireball):

That’s right, it’s not your imagination, Ice Cream Sandwich adoption is going very, very slowly. You’ll notice update percentage gets progressively slower with each new version, but keep in mind the Android ecosystem is also getting progressively larger. Ice Cream Sandwich has to deal with many, many more models than √âclair did.

Updates are getting slower.
Eclair? Ice Cream Sandwich? burp Let’s not forget the other Android versions: Cupcake, Donut, Gingerbread, Honeycomb.
It’s obvious what’s going on here. Android is getting fat.
It’s time Android threw on some Richard Simmons Sweatin’ To The Oldies and burn some calories! Stop inhaling every new phone Samsung and HTC come out with!
Android, you can’t eat away your fragmentation, eating only makes the fragmentation worse.