Crosby will go down as the 5th greatest player of all-time. Maybe some disagree and have him 7th or 8th or whatever - but he's certainly in the running for 5th. And the biggest reason why is his consistency throughout his prime (so those specific years).
In every single season he played here, he was either the best player, or in contention for being the best player. Entering any of those seasons - there's not a single season on this list where if you ask any GM across the league "if you could take only one player going into next season for one season only, who do you take" where majority don't pick Crosby #1, most of the time unanimously. (maybe on an exceptional basis he finishes behind Ovi once or twice). He was just as good in the playoffs, as he was in the regular season in that stretch.
Forsberg - he might be in the top 50 of all-time. On a recent top 100 listed made on the history forum, he finished 51st for example.
If I ask the similar question, "going into every season, for one year only pick one player who do you pick" - I'd argue Forsberg finishes outside the top 5 players picked more often then he finishes in the top 5. Compared to Crosby, #1 probably every year, most of the time probably unanimously, and at the very most #2 once or twice.
Also - Forsberg is one player who actually makes Crosby's injured prime look good.
This should be unanimous.
I don't think he finishes outside the top 5 in any of the seasons, except maybe 95-96. After that, the only people ever really considered better at points were Lemieux, Jagr, Hasek and Sakic.