Tor is more "centralized" than CA's?
Just numerically, this is true. There are 7 directory authorities that matter in Tor, vs over 100 certificate authorities.
In the CA system
any one of those 100 certificate authorities can break your security - 100 single points of failure. In Tor that's just 7 single points of failure, and IIRC Tor does have a n of m scheme for directory authorities.
As the experts have known for years, you can do
even worse than centralization, significantly worse: you can have numerous points of failure distributed around the world where failure of any one breaks your security. The certificate authority system is exactly that.