Reminder that the "infinitely growing blockchain" is a myth - for the answer look no further than the statement "Bitcoin is a system of incentives"

I have posted about this in the past...so sorry for repeating myself, but "Bitcoin is a system of incentives" to me is up there with "Bitcoin is P2P Cash"

Miners have no incentive to keep "really old" spent outputs. So they will naturally not keep them. The blockchain will not grow infinitely as it will always be pruned of old spent transactions.

"old spent transactions" might be defined by some miners as a spent transactions buried under 3 years of blocks.

Only the most rabid of extreme purists would ever think any community would consider for a second to follow an attacked chain (even with its higher hashrate) that rolls back years of transactions!

edit: "the most rabid of extreme purists " sounds better than "the most extreme of rabid purists"