Small form factors are great for computing on the go and do a decent job of consumption. It will take a break through in interfaces and input controllers before we can actually be productive with a phone, but really its just air keyboards and projection onto the air to make a decent workstation. Or we just plug it in. Phones are still a very long way away from the performance of PCs despite their Mhz and core counts but CPU core power consumption is gradually decreasing to meet them
But people keep saying that current desktops are so fast that people can do anything on them but its simply not true. Imagine I gave you 100,000x the computing power, you and I would find new novel apps involving progressively smarter and more capable learning software. Algorithms we currently run in the “cloud” would be executable on the local machine at a lot less expense. The software you find on PCs today is what will run, there is after all no point writing a program that needs a computer that has computation power far in excess of what one can make.
What we are seeing is the end of the Mhz race as single threaded performance crawls to a meagre 10% gain every 2 years instead of more than 100% every 2 years off the back of Moore’s law. Further to that the core explosion stopped at quads because no one could utilise the additional cores and the memory bus couldn’t keep up. Modern CPUs are a cache with a small bit of logic on the side that represents the cores.
The tech industry is finding one way it can go is smaller and less power consumption, so they will pursue that until it too stops scaling. But don’t misconstrue the hardware scaling crysis for a lack of need for the performance, we can always do cleverer things with more performance, its still a concern we have to think about constantly as programmers.