most of the 21m on-chain bitcoins will be used to provide liquidity (time value of money) for higher layers for a fee - translated into miners' fee. LN, Ark style coin-pools, all based on parcellating big chunks of bitcoin and selling their use to end-users in a non-custodial way
a good-enough covenants based coin-pool tradeoff can compress 1000s of "optional UTXOs" into one on-chain UTXO, similar to the way LN is compressing 1000s of txns into one on-chain txn
LN and ark style coin-pools are not competing, but are complementary. one is compressing the amount of times you can transact, the other compresses the amount of people who can hold a non-custodial movable balance - movable off-chain
LN solved bitcoin the way planes solved Fedex - but the last mile still remained a bottleneck. no matter how many planes you have, you still need to get the delivery to someone's home. covenants can solve LNs last mile problem