Why can't everything be FPGAs?

Then you could have programs dynamically create hardware depending on their needs.

>>17
Citation needed. Let's say I am a video producer and I edit videos and audio all day long. I sincerely doubt that there is a FPGA computer working today that performs this kind of task more efficiently* than the standard general purpose desktop computers today.

* Pick any metric you want and I still think that FPGA computers will be slower