Okay so the original poster kinda rigged teh question a bit with the now part as both guys have only played in 5 NHL seasons.
But lets look at what they did in those 5 seasons (and especially with Sid being 2 years younger) and try to find more than a handful of guys who ah better 1st 5 seasons in the history of the NHL.
05-06: 81 GP, 39 G, 63 A, 102 P (Sixth overall in scoring)
06-07: 79 GP, 36 G, 84 A, 120 P (First overall in scoring)
07-08: 53 GP, 24 G, 48 A, 72 P (Second overall in PPG)
08-09: 77 GP, 33 G, 70 A, 103 P (Third overall in scoring)
09-10: 81 GP, 51 G, 58 A, 109 P (Second overall in scoring)
05-06: 81 GP, 52 G, 54 A, 106 P (Third overall in scoring)
06-07: 82 GP, 46 G, 46 A, 92 P (Thirteenth overall in scoring)
07-08: 82 GP, 65 G, 47 A, 112 P (First overall in scoring)
08-09: 79 GP, 56 G, 54 A, 110 P (Second overall in scoring)
09-10: 72 GP, 50 G, 59 A, 109 P (Second overall in scoring)
If you can you more than the digits on your hands it would be very surprising. I can think of 4 who are in the same ball park as these 2 guys, to me that makes them generational players.
I don't think asking a question other than the one that lets you give the answer you want to give is "rigging" the question so long as the OP isn't equivocating or trying to imply substitute the answer to the harder one for the answer to the easier one.
I admit they have probably had the 3rd and 4th best "first five seasons" among forwards since expansion. That doesn't mean they're going to end their career 3rd and 4th among forwards since then though.
First, the higher you're on pace to be, the less room there is to exceed expectations and the more room there is to disappoint. A player with a spectacular first x years will, on average, not rank as high in the rest of his career as his first x years.
Secondly, their ranking is relying primarily on their first and second, and first and third, seasons respectively after which they both plateued very very early, so as their first two seasons, which blow most other player's out of the water, become a smaller part of the sample size their numbers will be less impressive.