Some of these instutions/layers are starting to pop up in btc w/ Fedimint, Liquid, etc. I think that these will be really crucial in the end, and the ultimate means by which most people interact w/ btc.
When we do AMAs, I always ask the Theilism, "what's something you believe about bitcoin that no other bitcoiner believes?" The one answer I heard the most was "most people will use custodial forms of bitcoin."
Completely unrelated but the most surprising answer came from @ODELL which was something to the effect of "bitcoin will be used to pay for armies of autonomous drone assassins."