I do wonder about the relationship between numbers and progress in challenging areas of theoretical physics. It can't be linear, and I sometimes suspect that (in fad-bloated fields) 90% or so of the researchers could, with reasonable confidence, be predicted to have a relatively negligible likelihood of producing a significant advance. (Assuming, for the sake of argument, that there is such a thing as a potential "significant advance" in the field in question, and reading "relative" as relative to members of the 10%.)
I also suspect that this suspicion may be quite wrong. Words and ideas I offer here may be used freely and without attribution.