One of the things Apple changed was how the software was perceived for phones.

Nokia (or the others) didn't update that much the firmwares for the old models. They just fixed the problems and added features to the new models. They were coming from simple phones that were not flashable in the beginning and they just wanted to sell more phones instead of supporting the old ones.

It's ironic how Apple is selling amazing amounts of phones with just few models and upgrading the software and features few times a year.