I do not think Crosby has high enough peak to surpass several forwards outside of Big3. Take Jagr, for example:
Crosby, 7 best % leads over #10 in points
32-27-26-19-17-15-14
Jagr, 7 best % leads over #10 in points
43-39-36-32-32-29-22
Crosby's most productive season would be Jagr's 4th best in terms of relative dominance over the field, and Crosby's 2nd-best season would be Jagr's 7th-best. To put it another way, peak Crosby would be consistently 10-15 points behind peak Jagr. That's a bit too much of a gap to cover with better defense and more team success, especially considering the fact that Jagr was a visibly better goal-scorer.
Now take Lafleur, 7 best % leads over #10 in points
52-51-42-33-26-25
Granted, those 6 seasons is all Lafleur has in terms of elite seasons, and Crosby already beats him on longevity pretty easily, but that gap in the very best years! I am still not sure I have come around on Crosby>Lafleur.
Now, take Mikita - since the league was smaller back then, it is probably fair to look at his point leads over #5 in points, not #10:
Crosby, 7 best % leads over #10 in points
32-27-26-19-17-15-14
Mikita, 7 best % leads over #5 in points
49-30-22-13-12-8-8
On the tail end, Crosby looks better, but again, the peak years favor Mikita.
And then there are goal-scoring legends like Richard and Bobby Hull, and Beliveau, who is the definition of well-roundedness and leadership, and we come to the second problem in Crosby's comparisons with all-time greats: he does not have a defining trait.
If we put a lot of weight on team success and playoffs, how can we rank Crosby ahead of Richard and Beliveau?
If we put a lot of weight on individual hardware, how can we not pick Jagr and Bobby Hull (and probably Mikita and Esposito) ahead of him?