I don't remember them sacrificing people before Sauron suggested it. Then again I could be mistaken.
Anyway, it's entirely possible (and probable) that Numenor would have gotten itself sunk eventually. But what-ifs are not important. It remains that Sauron did poison the people against the Valar. It is Sauron who pushed them to madness and death and evil.
He is only there because the Valar allowed him to be. The Valar's failing is a cause of the death of Numenor is all I'm saying.
I am enjoying this discussion though.