That's not really evidence of anything, other than historically being injury-prone. You're suggesting some predictive measures here. And in terms of predictive measures, I hear what you're saying. I can see the argument that Mantha should still get better and, if he stays healthy, has a chance to blow the doors off. I'm not saying that can't happen, but I'm just not expecting it.
Mantha was a dog up until about 1.5-2 years ago. Big and skilled of course, but he was lazy, was hesitant to engage, seemed afraid to try to dominate. Eventually a switch flipped and he became the player he is now. I think that was his big breakthrough. I don't see much more upside in him. Like I said, hitting 35+ and sniffing 40 one of the next few years seems plausible. But forwards, on average, peak at about 27. Of the top-20 goal scorers last season, 15 of them were under 27 years old. This next season is his age-26 season. He doesn't have much time before he hits crests the peak of his career. Could he be the exception? Sure, but I think we're setting ourselves up for disappointment if we expect that.