The target market is never upgraders. Camera companies know that the average consumer is not buying a new $2000 plus camera every 3 or 4 years. The target market is probably still people moving from DSLR to mirrorless, those going from lower tier models to higher, people who have skipped one or two generations of the same model, as well as people adding a 2nd camera to perhaps supplement a crop camera with full frame, or vice versa, and 1st time camera buyers. Upgrades are slow, not because companies are trying to trickle out upgrades. Upgrades are slow and minimal because camera tech has been mature for many years now. It's really that simple. We don't need some kind of conspiracy theory.