The mining pools are responsible for the high fees. I still remember what happened in 2017, when some of the mining pools rejected a lot of transactions with low fee, although they were having a lot of space left with the 1 MB block size. Instead of using the full 1 MB size, some of them were using only 300KB or 400 KB. I don't have anything against prioritizing high fee transactions. But rejecting the low fee transactions and asking for a higher fee looks like plain blackmail for me.