I think the comparisons are being brought out because he is looking for close to Kane money in a contract (15.22% - $12.4 AAV).
I don't think there is any chance that the Leafs pay him anywhere close to 12.4m...
UFA contracts and RFA contracts really shouldn't be compared anyway.
I do not agree that he has achieved more then Kane in his ELC. Less Points, Less Goals and with IMO more help. But for the sake of our argument here, let's say Kane and Marner had equal ELC.
Marner was better, and I disagree that he had more help.
First off, if we want to go by raw points, Kane had less at time of signing, despite the huge advantage in PP time/production because of the era. He also had a lower P/G at time of signing.
Kane had 168 points in 188 games. This is a 0.89 P/G.
Marner has 224 points in 241 games. This is a 0.93 P/G.
How about raw peak production? At time of signing, Kane's peak was 72 points. His pace in the season he signed was 82 points. Marner's peak is 94 points.
Goals? Kane had 55 goals and a 0.29 G/G and Marner has 67 goals and a 0.28 G/G, so pretty similar, though Kane had a much higher percentage of his on the PP.
When we look closer at the data and their rates of production, Marner is clearly better again:
Marner: ES 2.33p/60, 1.90p1/60 ---- PP 7.02p/60, 4.59p1/60
Kane: ES 2.22p/60, 1.70p1/60 ------- PP 6.24p/60, 4.22p1/60
It should also be noted that this above P/60 comparison overvalues Kane in terms of their contract valuation at time of signing. This includes Kane's 3rd year (which was his best), but 3/4 of that season happened after he signed (when he increased his production further). Doing those calculations by hand would be way too difficult, but if somebody else has the numbers at time of signing, I'd love to see them. This however does show, that even including Kane's best stretch which wasn't a factor in the signing, Marner still surpasses him in every way.
It should also be noted that Kane's signing came in the year after the cap only rose
0.1m. I know we're all freaking out because of the abnormally low 2m increase this year, so I can't imagine that didn't play into projections and contracts signed during that offseason/beginning of the season, especially since it was so insanely less than every other year under the salary cap to that date.
Marner has earned more than Kane did at time of signing their post-ELC contracts. How much more is a matter for debate, but he's definitely earned more.