There must be hundreds of these things passing unnoticed through our solar system. I'm not convinced that there are a lot more of them, we just have better detection equipment. Even the Russian meteor was only picked up due to the large number of dashcams that people now use.
Maybe I'm wrong, but if we do get a catastrophic asteroid hitting the earth there isn't a great deal we could do about it so might as well live on and not worry about it :)