Mining cryptocurrency now only stop when the earth will not have at least two computers that can confirm the transfer. Cryptocurrency is the future. Soon to be profession to invent. We live at the beginning of the cryptocurrency age.
Cryptocurrency can exist without miners. It is just the algo. Coins can switch to PoS or DPoS if required. So miners will be forever in Bitcoin only(I guess algorithm will not being changed), got paid for work with transaction fees, others may switch to another ecologically friendly algo imo