Crosby is not challenging the length of Howe's prime right now. He's a half decade away from that even being a consideration, and even then it would still be Howe. Howe has the better peak. Crosby almost certainly won't challenge Howe's longevity. Inventing convoluted measures for Crosby's benefit in order to attempt to boost him, as seen in the post quoted by the poster that I quoted, doesn't make him any closer.
The first bolded. It depends what you mean by "prime". That can be just as convoluted.
To the 2nd bolded, it isn't about Crosby challenging Howe nor should you be making any assumptions about what Crosby does from here on in; it is the significance of Crosby hanging with Howe after their first 14 seasons.
According to the HOH Best player in the world thread, Howe wasn't in the in the conversation after the 62-63 season ( IMO, I would make it the 63-64 season as he has a dominant playoffs), and while Top 5 Art Ross finishes in his era are good, they do not compare with a Top 5 finish in the current era strictly from a statistical perspective. IMO, Crosby can finish in the Top Ten in scoring to, in theory, stay in his "prime" like Howe did.
So, in this context, why can't there be a discussion about comparing their first 14 seasons?
You seem to want to shut that down because Howe wins the "peak" debate, yet there are many examples of players with lower peaks being rated higher than others in the HOH Top 100 project, look no further than Howe vs. Mario.
Yes, Howe had the better peak season, but he was never able to reach that peak again, and other players reached those same "peak" point totals and PPGs a few years later which, IMO, leaves one wondering where to place "peak" Howe. At best, it is above every other player besides the Big 3 but is not on their level. He has three other Art Ross win seasons that are equaled by the best seasons of Hull, Mikita, Beliveau and Richard. His playoff resume by 1960 was very good but not befitting his regular season stature. He was T2 in points, 3rd in PPG (well behind Beliveau) and had the 2nd or 3rd best playoff run during that time period. It can be argued that Beliveau and Geoffrion were the superior performers.
Crosby reasonably has two partial seasons (10/11 and 13/14) that were on the level of three of Howe's four Art Ross seasons in a row and his two Art Ross wins are arguably superior to Howe's 56/57 win. I would argue that Crosby was just as dominant, maybe moreso, on a per games basis mainly on the strength of hitting his prime almost from the get go. His playoff resume is clearly superior to Howe's and is befitting his regular season stature of being the dominant per game performer.
So we are left with injuries being the primary reason that Howe would be ahead of Crosby after 14 seasons but I think it is very reasonable to say they are on the same tier.