Verizon is too busy trying to make sure that it can remove native applications from Android in favor of 'Verizon only' services. There is no financial incentive for them to move onto ICS with any speed. Despite the fact that ICS has been out, that almost all phone manufacturers have established which phones can and cannot be updated while still providing a good user experience, Verizon isn't updating much of anything.
Too busy spending my money, I guess, on executive back scratchers.