This is a GREAT thread.
Martin St. Louis put up 774 points from age 30 to age 40(closest Kane comparable player?). I see absolutely no reason that Patrick Kane cannot match that production, or come close. St. Louis only has 147 more points than Kane, right now. He is currently 581 points behind Mikita. If he matches St. Louis' production from 30-40, he ends up with 1660 points.
My prediction? He will retire as the greatest American-born player of all time, the all-time leading scorer of the Blackhawks, and, quite possibly, top 10 EVER in points. Yeah, it's a bold prediction. So what. Convince me he can't do it. Better yet, convince HIM he can't do it. I bet you can't.
What's beautiful about Kane is, like St. Louis, his physical tools have almost nothing to do with his production. He's just that much smarter than everyone on the ice.
He will age like a fine wine.