I don't like seeing the Bitcoin users as collectivists. Pretty much the opposite. Running a Bitcoin node is a process dedicated to the individual. Each individual has the same rights, as anyone, to change their rules with no one's permission. The Bitcoin network never tells you what to do. You're just receiving information and instruct based on the rules you've chosen to follow.
Those who are running full node they do not get anything but contributing in the ecosystem without any selfish act.
No, no. They pretty much do gain benefits. Running a full node grants you privacy, security, and self-sovereignty over all. In fact, running a full node does a lot more contribution to the person running it, than to the network bandwidth-wise.