you're not wrong.

i'm baffled every time i hear someone say "its the only thing in the world you can't possibly make more of!" like its a law of physics or something.

that said... any individual or group (of any size), can refuse a fork that would lift the limit. and nobody could unilaterally force them to accept it - only entice them with incentives. so as long as their will stands, for them it *is* like a law of physics. everyone on the fork allowed their own physical laws to bend and break for false deus ex machina promises of easier/better/cheaper, while the 21m crowd are still living in their consistent timeline.

i'll let your imagination do the rest wrt what the character and futures of those two distinct societies will look like, given their founding stories.