It appears that the “rapid expansion” has already ended.
The attack could be 50x worse next time. If your roof was damaged by a storm 50x less severe than the worst case, and it stopped raining, would you take the opportunity to reinforce your roof to prepare it for the worst case, or would you say “it’s not raining now, so there’s no need to do anything”?
Are we to propose changes to Bitcoin once we reach 100 million users? Or 200 million users?
If it causes nodes to become harder to sync, then… obviously yes. Since the recent UTXO bloat has come from data spam, however, the low-hanging fruit is to filter data spam, as this “use case” artificially bloats the UTXO set much faster than normal usage. If and when there are enough monetary users that node sync times or decentralization start to become significantly impacted, then other scaling methods will need to be employed, since filtering spam would do nothing in that case.
The Bitcoin network has faced this many times in the past and will again in the future.
Yes, and all previous times, node operators rose up to oppose data spam, which eventually succeeded at driving it away.
Pricing out payments does not make sense - this implies you have the right to confirmed transactions at any time for any fee rate. It is nonsensical to ignore a dynamic fee market for transactions.
On the contrary; what is indeed nonsensical is to allow data spam to outcompete payments on a payment network.
Transaction fees are currently low, which can only mean the “spam waves” have ended long before BIP-110. I don’t see a reason for change based on the lack of evidence.
Again, we should take this opportunity to repair the damage caused by the storm; it would be very foolish to assume that the storm cannot return.