Wasteful in the mobile segment yes but the desktop segment no especially since there are games and video editing software that use more than 4 threads
The reason why Intel hasn't brought CPU computing capability up since Sandy Bridge is because AMD hasn't improved their CPU computing capability much at all since the Phenom II. Instead, Intel has their eyes on ARM and the future of computing and has put all their emphasis on efficiency and their integrated GPUs
Video editing software is not realtime dependent. And there are workstation solutions for that if you really need.
Games using more than 4 threads? How many games are that?
For me it seems people try to hide behind the competition argument and pull up AMD as a shield. It simply holds no truth.
Try think on what OEMs and the very wast majority of users demand. Then try look besides your own wishes that seems to be more cores.
You might find out that it got nothing with competition, simply Intel not serving your exact wishes, but rather the wast majority wishes instead.