What I'm saying is that you can build 20th level characters that can deal with anything publisbed. I mean yes you could build a monster that would automatically win. But that would be a nonstandard monster (which should e ist if people are playing in a nonstandard way.) Cthulhlu how ever is a standard monster which means he is fair game to get killed.
Standard enemies will never stand up as written against people who are using non standard ways to fight them. Yes cthulhu is scary. But he has stats so if he exist as written he can die. If a dm wants to change him to be a bigger threat who is prepared with counter measures that is fine. But that is not how he is written.
See that's the problem. He isn't written as having done any of the planning he could have done. And since we are looking at him as written he is very killable. He is still a challenge if you try to attack him in standard ways. In fact attacking him in standard ways is almost suicide. So you have to attack him in non-standard ways like Anzyr suggest.
I was going to make a snarky comment about how we don't have to value anything that Sean says now that he is not with Paizo. So imagine my surprise when as soon as he can stop toeing the party line he becomes much more helpful. Instead of getting the standard this is the way things are and you better like it, we get the curtain pulled back. I hope this new more personable SKR sticks around