It was an unfair situation for Conan, but ultimately, NBC is a business and The Tonight Show is a hallmark show for the network. Once Conan took over, the ratings started dropping. And on top of that, the new show that Leno started hosting wasn't doing well either. Although it was unfair, it was a smart business decision on NBC's behalf.
Yes, NBC was wrong to oust O'Brien from the tonight show, because he is a funny guy and honestly a decent person. He was an inspiring person who went for his dreams and was successful. He has a lot of things going for him and he was a lot easier to find when he was on NBC.
I think Conan was treated horrible by NBC and was never given a fair chance. I think they did not stay with his show long enough to see if it would be a success or not. I always have enjoyed him and would have liked to see how he would have done. The way the situation was handled was unfair.
First off NBC owns the station and so it does not matter what anyone thinks, they get to do what they want with what they pay for. Second off, the viewers of NBC are generally more intellectual and like a smarter, well thought out comedy. Conan is not funny and his comedy is physical based and sophomoric.