Miners don't make the rules, users (the economic majority) do. That's another misconception.
Well, last time I checked it's the miners that were hashing, and therefore making the rules.
Of course without users the whole thing is pointless, but without the miners have fun forking anything.
"What he can gain" is fixed.
That's exactly where you're oversimplifying, because it isn't. If you 51% attack bitcoin, chances are you're going to hurt confidence in the network and therefore the value, thereby changing your expected gain. You're forgetting an important unknown in this equation.
So basically you're chasing a moving target, one for which it's also extremely hard to know whether you're even close to it.
I have defined what "really needed hashrate" means, an argument for the needed hashrate being low is not really a reply.
I never said it should be low. I didn't reply either, I pointed out that even though the question might have a theoretical answer it's not in our reach and therefore not very interesting to pursue any further. Of course, the more hashrate the best, there simply is no way to accurately declare the network to be "secure", or "insecure" without resorting to wild guesses and approximations that make the whole exercise pointless.
So because we can't know something with 100% certainty we're supposed to just bury our heads in the sand and not try to analyze, estimate and improve the system?
That's not what I said, as a general thing I try to refrain from using "we should" or "we shouldn't" when it comes to Bitcoin.
I said multiple times that I don't know what will happen
Good. So we're on the same page, forgive me but I'm not the kind to dig through histories and I didn't happen to encounter this particular string of words in your previous posts in this thread.