I mean, you should be convinced. Konecny's career year in points was 68, and his career PPG is 0.71. Setting aside Marner's rookie year, his career low is 67, and those were in 59 and 55 game seasons; his career PPG is 1.11, and he's never had a season with lower PPG than TK's career average. TK probably has another 10-15 points a year in him with Marner's linemates, but I don't see him having a 3 year run of 97, 99, and 85 points no matter who he's working with.
TK's a great player, and he brings more than points, but Marner's offensive production is genuinely on a level higher than TK's.