I don't think the problem people are complaining about Android fragmentation is a phone company decides it's not worth the trouble to build out ICS for a 2 year old phone but rather there's still brand new Android 2.x on sale today with no upgrade path.

Optimus L3 was released earlier this year, ships with 2.3 with no foreseeable upgrade path (thanks to its low price). The software is outdated the moment it was released.

I'm looking for Android phone today and still undecided of what to get (inclined to get HTC One X) because I'm unsure whether it will get a 4.1 update or not.