I disagree, I think that people can be better than their influences. Nowhere was it ever stated that a person's influences will always be better than they themselves. Take Michael Jordan, I'm sure he had influences growing up, but he's arguably the greatest basketball player of all time. Now relate that back to music, everyone has had to have influences somewhere along the way, Hendrix had influences, Led Zeppelin had influences, Black Sabbath had influences. Those people/bands are pretty much some of the biggest and most influential names in rock and roll, if what you state is true, their influences must have been greater than them. But does everyone even know what influenced them? No, but if they were greater you would think that people would, right?

Also, your theory doesn't take into account influences from different genres of music as well.

Basically, an influence is only that, an influence. They don't have to be better than you, only make you think and inspire you.