As many of the members above have said, if Bitcoin fees go up and it happens for a very long time, the first thing the devs do is find a way out so that Bitcoin fees go down again. The ups and downs in Bitcoin fees won't happen forever, maybe only for a few days. Improvisations will continue to be made, updates will also continue to be made to improve the system in the Bitcoin Blockchain so that it is able to process more transactions and at low costs.