i continue to think you're focusing on the wrong metric: nodes.
if tx fees go to $100 with 1MB, how many 3rd world ppl can afford that? answer: none. and when fees go that high consistently, they won't even bother with Bitcoin.
what good is it then to run nodes when Metcalfe's Law squares with user growth?
Users is the wrong metric too. Paypal has an enormous number of users. Conventional banking has even more.
Bitcoin has to remain (or arguably return to a state of being) decentralized in a meaningful way and
also get users, or it is just a waste of time. The metric has to be both.