Maybe OP should have slowed down with anticipation on what the future hold for us as it has to do with Bitcoin because the crypto space is still an evolving one and between now and 2140 is a very long time enough for a whole lot to happen both with advancement and revolutionary changes in the space. Whatever we may say now about the future of Bitcoin are mostly speculative because no one has an exact ideas on with it would be else they will just go and hijack the whole system.
But that's how humans think, like what will happen tomorrow, whether you'll still be alive or not is a mystery, but we still believe we will survive, and then plan what we will do before tomorrow comes. We may not be able to comment on 2140 because that's no longer your and my world, but your mind can imagine what might happen if Bitcoin served as an incentive for miners to earn profits beyond confirming transactions.
If not 2140, imagine if tomorrow there are no more Bitcoins to mine because they've run out. The context would be the same, and then enter those questions.