Bitcoin is not a democracy. If "the majority" of nodes get to decide what the bitcoin protocol is then a government could just spin up a a couple million nodes and change the 21 million hard cap. That isn't how it works.

The rolling set of nodes that *verify bitcoin received in exchange for something else* have 100% of the hard power over the protocol rules.

You need to be producing/trading something of value in exchange for bitcoin in order for your act of transaction verification to have an impact on the network. If the bitcoin you receive does not comply with your version of the protocol then verification fails and you stop providing economic value to whoever sent you the "bitcoin". The rolling set of people doing this determine what the protocol is.