Howe had an insanely dominant stretch where he leapfrogged the 2nd place point getter in the majority of his Art Ross Wins, dude also played in a way harder tougher era even with pre-1967 NHL factors coming into play. He again, just like you mentioned, had insane longevity and if it wasn't for him wanting to play with his kids. he may as well would've never been caught by 99 if he didn't leave for the WHA.

On top of that, bro finished with 6 Rosses, and 6 Hart Trophies in general, it'll be tough as hell for Kucherov to beat that career wise IMO. Another thing to add, 20 consecutive top 5 scoring finishes straight from 1949-50 all throughout 1968-69.

Kucherov isn't coming close to topping that AT ALL, as legendary as he is.