I think the flagship manufacturers' approach has always been to find the two or three things consumers will pay most for and aggressively optimise for them. So

I think the flagship manufacturers' approach has always been to find the two or three things consumers will pay most for and aggressively optimise for them. So phones got thinner, cameras and screens got progressively better, for a few generations at least. Other features that got in the way and didn't add a huge amount to the phone's mass market appeal got dropped. It will certainly be interesting to see how the manufacturers continue to find ways to differentiate themselves. Right now, unsurprisingly, all the hype seems to be focused around AI. So possibly future phones will be ruthlessly optimised for running LLM models. But if, instead, the phone manufacturers just decide to use cloud-hosted AI (or if the hype around AI dies down), then they'll need something else. The foldable form factor is the only other one that occurs to me right now.