Yeah, I remember how SegWit dropped the transaction prices and I guess something similar will have to be created so that more transactions fits into one block. Then maybe the block reward payed only by a transaction fee will be enough.
There is yet the very first solution of increasing the blocks size ! The block size was limited at first time because of technical and networking difficulties (largely surpassed now), and the increasing was always part of the Bitcoin conception. It is what was implemented for Bitcoin-Cash, then majority of miners refused the migration so it is what have land to the fork from which BCH resulted.
Miners then just won't abandon the income constituted from the tx fees !!