Just my opinion, but most phones won't have the horsepower to run ICS and the carriers are always loathe to spend manpower porting a new release to a old phone

Just my opinion, but most phones won't have the horsepower to run ICS and the carriers are always loathe to spend manpower porting a new release to a old phone when what they really want is for you to buy a new phone an re-up for another 2 years.