Well Chris, if it's not a yes/no question then there isn't a definitive answer to "Has anyone surpassed O Sensei?" (and I think the OP was asking the question with regard to technical expertise). If that's the case then fair enough. Subsequent statements regarding the abilities of others, with O Sensei being used as the so-to-speak standard candle of measurement, must be seen in the same light.
Sure, but you're setting up a straw man argument here - I don't think that anyone who's made such statements would say that it's a matter of objective fact.
On the other hand, I also think that there are people who are in very good positions to offer opinions on the matter that have made such statements - including people who were actually there.