What no one is talking about: If #Bitcoin becomes more diversified duo to more adoption, then the amount of UTXOs will increase, which will make fees incredible higher than they are right now.
Discussion
People have been talking about this for many years. Layers will work this out just fine.
Self-custodial is not a question but the path of financial evolution. If you wait long enough, only self-custodial will survive. And so will the on-chain fees, for providing liquidity for second layer solutions, still play a big role in future.