The 21M can absolutely be changed. It's not a law of physics, it's just a line of code that can be changed. If enough people agree to it, it can be changed, the

The 21M can absolutely be changed. It's not a law of physics, it's just a line of code that can be changed. If enough people agree to it, it can be changed, they can even change the number of coins you get for successfully mining a block.