There are projects that have already employed this strategy. I think the best of which is probably Monero with its tail emission. There is no reason, in my opinion, for Bitcoin, to do this. If Monero's choice is the winner, we will move over there.

But changing Bitcoin's monetary policy mid-stream would be the fastest way to destroy this experiment. Satoshi may have been able to pull this off in the first year or two, but not anymore. No one could. Not even her/him/them.