I'd bet if you were a large enough customer they could find a way to cough up some upgrades.
Ohio MARCS has mandated Radio Authentication, and there are thousands of XTS/XTL radios around the state; Motorola will not do the Authentication update for radios with firmware older than R15, and will not sell firmware updates, no matter how big a stink anyone makes. Our Motorola rep told me that they won't sell firmware updates to anyone, period. Apparently it's not even in the system anymore.
My neighboring agency is a faithful Motorola customer with hundreds of XTS/XTL radios; ditto Ohio MARCS, with thousands of XTS/XTL radios around the state. Motorola won't even make an exception for them.
Face it, they're trying to get everyone off the platform, and sell new radios. Problem for them around here is, no one is going to buy a Motorola radio for double the price of a Harris or Kenwood radio unless they're a die-hard /\/\ fanatic.