[throwaway248329]

Changing the miner subsidy amount would require a hard-fork, so the chain would split in two chains with a shared history, the original with only 21M coins and the new chain without the cap. And once that happens, it would be in everyone's financial interest to get rid of their inflationary coins and sell them for original Bitcoin.

So unless all the world governments decide to make it illegal to mine the old chain, it wouldn't work.

[osigurdson]

I don't believe that a hard fork necessarily results in a split of the chain. If all miners accept the hard fork then there is no split in the chain - new blocks require miners. My understanding is this has happened before.

https://phemex.com/academy/bitcoin-hard-fork-vs-soft-fork

[throwaway248329]

Yes, but as long as some miners stay on the old chain, it will live. Hard fork also requires the users to switch to that new client, otherwise they won't be able to accept the new blocks from the forked chain.