Another scenario - if person A has all paid relays and person B has free relays, some of their 2nd & 3rd degree friends will not be able to view each posts - if, for example, events are not published to the relay list or for other reasons.
An experiment is to set a new npub, follow a few Ppl, add common relays and only read from paid relays. Look for a high following profile and compare from this ‘new npub’ vs that high profile’s npub - you might notice some posts missed out and not all people unaccessible via this “new npub”. My worry is current mix will slow down global adoption instead of improve it
