Crosby the goalscorer is a garbage man, somewhat like Esposito, but lacking the size and flair. And just like Esposito is never mentioned with Richard and Bobby Hull despite being statistically similar, Crosby's name is often an afterthought when it comes to great goal-scorers of our time. He does not look like a goal-scorer, and thus he is not treated like one.
In all fairness though, the distance betweem Ovechkin and Stamkos/Kovalchuk and then a similar, if not greater distance between Stamkos/Kovalchuk and other good goal-scorers makes the distinction of a 4th-best or top5 goal-scorer rather unimportant, because such player is not anywhere close to the top or even the 3rd place.
Crosby belongs to this "third tier" of good goal-scorers of our time, along with Nash, Perry, Heatley, Tarasenko, Malkin, Tavares, and I am probably forgetting someone. Can one make an argument that Crosby as a goal-scorer is a bit better than all of them? Probably. Can one, just as easily, make an argument that a significant number of these people are better goal-scorers than Crosby? I think yes.
For example, one can put a lot of weight on consistency and argue that Heatley managed five consecuitive top10 finishes and two back-to-back top5 finishes and Tarasenko has already managed three consecuitive top5 finishes, while Crosby has only back-to-back top10 finishes, and finished top10 in goals only four times.
As for career projections, in his seven best seasons Crosby is currently 46th all-time on the VsX-adjusted goals the History board usually uses. That's probably his fair place, somewhere between Keith Tkachuk and Mike Gartner. If he exhibits better-than-average longevity and given the low-scoring era, he should land somewhere around 40 on the career goals list as well. That would be 500-525 career goals.
600 career goals are most probably out of reach. He is 30 already, and he started this season with 382 career goals, so he needs 218 goals post-30. Only 37 players in the whole history did that, and at least 10 of them played in the 70s and 80s, when scoring was much higher. Many all-time greats fell short of 218 goals post-30, and the list includes Gretzky, Lemieux, and Yzerman (yes, health is a big factor post-30).