I would argue most did not get it wrong until within the last 500-600 years. Please remember the Jews did exactly the same thing in corrupting their religion; so are we any different? By the time Jeremiah came on the scene Judaism had evolved to a point where the Jews were setting up idols in the temple and worshiping other things all the while believing God was looking favorably on them.
People today no longer care about correct theology. They simply want to fashion God into however they perceive Him to be. The scriptures are very clear on the correct way of worshiping God. People simply choose to ignore it.
Personal interpretation of Scripture is the essence of protestantism. The Bible warns of itching ears, but some ignore the warning.
What does "wrong" entail? If we define "wrong" as anything but 5 point Calvinism, I think we're gonna have a tough time making that case historically. Augustine was the only person who even came close to that...and he didn't even go all the way. And I'm not sure, but I believe that view was a minority even within the Reformation.
To some extent you're right, Old Scratch sows his corruption even among religious folks. But there's a difference. God never promised the indefectibility of the Jews...but Christ promised the indefectibility of the Church. :)