In my opinion, I see one of two things happening:
1. Bitcoin L1 stays at the same fee rates as they are today, but does not achieve mass adoption. There is no hashrate exodus, or attack. Prices eventually cap at some price in the distant future.
That doesn't make any sense because if the miners don't get paid enough to continue hashing, then they'll have no choice BUT to turn of their ASICs.
Unless that argument assumes price will continue to surge ad infinitum.
2. Bitcoin L1 gets mass adopted either through using the UTXOs themselves or by using some project on L1 like Ordinals, Runes. Fees skyrocket to 100+ sats/vbyte, and regular people use Lightning instead. (This would copy Ethereum's outcome.) There is no hashrate exodus, or attack. Prices probably don't cap until 2140 or even later.
Notice how "increase the supply cap and print more bitcoins" is not an option.
That's because it's practically guaranteed to never happen. Nobody who owns Bitcoin will agree to let it become a money printer.
That's my first belief, but nothing is guaranteed especially if it means life or death for Bitcoin. It's highly improbable, but it's still a non-zero chance to happen.