Profitability of validation after all BTC is mined?

Maybe this is a dumb question, but I wanna know the answer. Obviously the low transaction cost is only one of a number of key factors pushing people to BTC/crypto, but I don’t see how it’s sustainable.

The way I understand it now, is that miners are given rewards for validating transactions. Similar to how Mastercard and visa collect a percentage of the transaction cost for validation/execution of the transaction.

But what happens once all the BTC is mined and the profitability of the mining industry plummets? From there I can only see two things happening. Miners/validators simply become the new visa/Mastercards of the world collecting ever increasing fees to maintain the network, or there is a massive fall off in the power of the proof-of-work network as miners take there operations offline since they can’t earn anything from being miners anymore?

What does the community think will happen once the final coin in mined? I apologize for my Ignorance on the subject in advance maybe the answer is obvious and I’m just not getting it.