Is there anything to stop the core devs saying we want unlimited bitcoin and changing the code to allow it. I mean, 21 million isn't much. 
There isn't any thing the developers can't do.
At the end of the day it is just a piece of software and at the same time it isn't.
I do think that , the developers won't do that , since they most likely will kill the very idea if bitcoins themselves.
It was created as such , when it is stagnant then people won't be able to buy new bitcoins denying the inflation , the price will sky rocket , for people who are holding will actually be Happy.
I think this whole period bitcoins is in , is a growth one right now , when the supply stops it might be able to just achieve a price that is more or less stable and not even low.
I hope they don't .