Bitcoin devs can do whatever they want, except that there is no law putting them in charge so if they attempt to commit fraud they lose everyone's respect which was the only thing giving them any power, and they get replaced by someone else. Which they don't want, which keeps pressure on them to behave well.
We can argue about the game theory and what exactly would happen if this was attempted today, but the point remains that double spend is possible and the Bitcoin white paper does not address this issue because it assumes Bitcoin code is set in stone. As soon as you consider that the protocol evolves and is subject to human manipulation, the white paper's guarantees all go out the window. This includes the 21 million bitcoin "limit".
And I think we can both further agree that someone that isn't us modifies the code of the Bitcoin node we run on our devices. Unless you're still running Bitcoin 0.1, but then you're actually not on the "Bitcoin" network as we know it today. There are pressures outside of your control that make it so that you have to update your node, and you have to run new code you probably haven't reviewed or approved yourself.
The only way to make Bitcoin work as defined by Satoshi is to have the code be 100% perfect and then not touch it, and that ship sailed a long time ago.
They also won't refund you for fraudulent charges unless you report them quickly enough.