"What's to stop social consensus from one day increasing the 21M hard cap if it can override core consensus in this way?"

This is retarded and so are you. It's called "a contract" and it's astounding how few bitcoiners are at all familiar with this object type.

This post also makes it clear you do not understand bitcoin either and the basic game theory that prevents inflation.

Bitcoiners are so dumb, I have become all but convinced the Great Retardation will not end until hyperbitcoinization + 1 century.