the concept of streaming 4k video over the internet was viewed by many to be impossible, at a particular point in time.
it's important to remain cognisant of our ideals and goals, as new innovations may re-shape what is possible, through time.
Discussion
That's a bad analogy. Bitcoin has a block size limit and an average 10 min block creation hard coded in the protocol.
The internet would have been very different today had a maximum bandwidth been hard coded in 1989.
There are about 1,000,000 active bitcoin addresses. Let say each address is own by a different person, which is not the case, that's 0.0125% of the world population. Blocks are full and there are currently over 290,000 unconfirmed transactions.
Self-custody for everyone is not possible. It is mathematically impossible.