I feel it depends on the auto maker, most are deliberately making changes to drive new sales (obivously), switch cars every 3-5 years at most, and the most cost effective place to do this (self driving R&D aside perhaps) are the tech 'gadgets'.
Tesla is breaking this trend, the Model S since 2013 is one of the longest runs of body shape out there, and with relatively minor changes happening (plus the regular OTA updates to help satiate our wants for latest and created) unscheduled does not promote the upgrade behavior. I think Tesla re-sale values support this, they are still in very high demand (judging by depreciation).