By Fred Brooks, a programmer's productivity can vary factor 20 (he referenced scientific studies), which does not necessarily correlate with years of experience. That was 1975, but I'd confirm this is quite possible today as well.
Question: as programmers' rates obviously (AFAIK) do not vary on such large scale, are industry's best workers heavily underpaid, or the market demand/pressure is just too low?
UPD. Relation to project management is that if this question is clarified, we could discuss which impact this can have on project management by bringing project business priority in relationship with this efficiency.