With 50% of the hashrate you're not Selfish Mining anymore; you're effectively able to take over the network since you now can outrun the other miners indefinitely.
I totally agree and that's why this kind of attack is not really a viable threat, because if you need 50% hashrate you can do whatever you like.I found this realistic model of selfish mining (as opposed to hypothetical theoretical models):
Source: https://medium.com/@ProfFaustus/the-caner-that-is-the-selfish-mining-fallacy-ed65c20a6ce7
where we can see that the selfish miner revenue (orange line) surpasses the honest miner (blue line) revenue very close to 50 percent hashrate.
If that's so, no point even discussing this kind of attack.
Thank you! This looks correct to me, well put and nice plot.
Also see: http://vixra.org/abs/1504.0072
That plot is from a blog of a Bitcoin Cash (BCH) supporter. He talks about various sophisticated statistical concepts, without showing the math, and even uses "miners will blacklist the IP address of selfish miners" as an argument. I wouldn't assign much credibility to that analysis, though it has some amount of truth, it is not a full, unbiased analysis of the situation. Even if his model is correct, selfish mining isn't the only attack I'm concerned about, as I have mentioned in previous posts of this thread.