What martial artists from Bruce Lee's time could have been better than him?

We know many Bruce Lee's fans say he was the best of all existing martial artists of his time. But I really have my doubts. I don't doubt Bruce was a real martial artist ( and not just an actor ) and that he was in great shape. But I think assertions such as "Bruce Lee was the greatest martial artist of his time" cannot be proven because I'm sure there were also several very good martial artists in the 60's and 70's in China, Korea, Japan, etc and maybe some of them unknown by most people all over the world.

What do you think?