With everything that bitcoin is made of, it cannot collapse, the mining continues until all the 210,000 blocks are completely mined, which is the 21 million Bitcoin in total, if my o more mining, then miners receive incentives from the transaction fees, which has nothing to do with bitcoin being in existence or not, because there are set protocols that must be in concession before anything can be done in using the network, not even the miners can change this or alter it.