It's a long term thinking, what would be the incentives to mine and use electricity when the block reward is close to 0 sats and the fees are low?
I personally think that by that time adoption will fix this issue as a lot a entities will want to move UTXOs. And if it's still too low we can adapt the block size so the fees are always something significantly rewarding for miners to spend electricity and secure the network.
Same behavior for a significant lack of block space and high fees, we could raise the block size by a few MBs. By 2100+ the bandwith debate might be less concerning as technology will propably have improved by a lot. As long as it's affordable for the poorest individual to run and maintain a full node.
