You already answered to yourself: the fee will be high
the second layers will see the majority of the transactions, indeed, but of the ones which make no sense to do on the layer one.
If there is low demand of blockspace, fee will be reduced and more transaction will be done again on the layer one.
We have already see this year blocks with at least 3 Bitcoin of fee. There still will be incentive for miners to keep their infrastracture online
Yes, the fee per transaction will be high, but there will be very few transactions occurring on the main chain. Will it be enough? Why would more transactions occur on the main chain as fees drop? Do lightning/liquid nodes have an incentive to “settle up”?
Remember that the second layers are fine for small and medium transactions. Larger one still require the layer one, and thats in an incentive to settle transaction
If there will be "few transactios", then the fee can't stay high for long. If they drop, more people will prefer send values here and not on second layer, increasing demand for blockspace. Is a cycle.
For my understanding, miners who are gone out of business its because they expanded more of what the current price allowed
