In a future, where electricity might be progressively more expensive, how will zcash miners keep mining?

This is my question.
There will always be the need for miners to mine the transactions or might the truthfulness of this statement change anytime? Will the fee need to increase with time so that the miners can afford the mining? I am thinking about mismanagement from all governments, where nations will reach a point where every energy will need to be regenerative an anything else will be unprofitable because of green taxations etc. (not wanting to draw a dystopia or such, just a question/thought experiment).

So in that scenario, how will zcash survive, when there might come times, where no one would want to afford electricity (more imporant industry/humans might need it more somwhere else).
Or will the mining of a transaction be extremly cheap in term of electricity? When all 21000000 ZEC was mined, will transactions be less costly to compute?

Can you elaborate your thoughts about this issue? I want to know more about the longevity of zcash even for several decades for example.

Thanks for your time,
with best regards,

There is a strong support for a PoS transition in the Zcash community. You will find it if you browse around. Cheers!