Personally I would pay a smallish fee for a new OS, but I wouldn't pay for fixes or smaller feature updates.

I can live with paying a fee because companies have to factor in the costs of developing and porting a new OS to older hardware. But, at the same time, they also have to factor in the cost of alienating and losing their old customer base when they try to sell their new hardware.

I look forward to a time when we can purchase mobile handset hardware and install the OS of our choice, much like we can with PCs and netbooks today.