Behind the full nodes are people and they can choose to run whatever code they want.
So? What's your point?
It is impossible to mine Dogecoin with Bitcoin ASICS, Dogecoin uses a different algorithm compared to Bitcoin.
I'm guessing you simply chose to ignore the argument. Dogecoin was simply an example.
Technically they can, practically it depends on whether the majority of nodes actually represent the economic majority or not, since nodes can easily be spoofed, this is why proof of work is so useful since it is a better measure of consensus because it can not easily be faked.
You suceeded in side stepping the whole of my argument to basically say nothing.
It doesn't matter that nodes can be spoofed. What matters is the nodes being run by the ones holding sizeable investements into the system. If the miners try to go against their will they will be bankrupted.