I mean, if he wanted to play until 42-43, yeah, he probably can do it. The big if hanging over has always been health, and all of this is contingent on that.
But I don't think he has any desire to play that long. He has always mentioned he would like to end his time in Russia, and that he wouldn't be one to hang around forever.
that said, if he's still highly productive, and his growing family is comfortable here, I think he might stick around. It also helps that the Caps are decent and have players around him he likes playing with. If that changed, it might make a difference.
Doing the math, if you figure he needs 272, that's a ton of goals still left.
He got 49 last year, but only 33 the year before. I think it's reasonable to consider him getting 40 this year without much debate. It might go up, it might go down. I think having talent on the Caps hurt for a bit actually means he has to press a bit more in the regular season, which could mean a higher output, but that's still an if.
I think it's reasonable to expect 40 for this year and probably next.
If that puts him at (272-25 [remainder of this year]-40 [next]=207) at 207, but at 35/36, that means he would need to have six more seasons of 35+ goals. I don't think that's unreasonable, but that's tough to think you'll see him still here at that point. Note, my math might be a bit off, because it's not completely my thing, but it's possible, not probable. What would make it way more likely is if he was somehow able to get 50 or very close in the next two or three seasons. If he did 3 years of 45-50 (this year and the subsequent 2), he would be within shooting distance of needing around ~ 140 in 5 or so seasons from 36-40ish. That would be much more likely.
I mean, with his shot, and his size, he can certainly get 30-35 goals in a season for as long as he wants, and as long as the PP works. Playing with Kuznetsov should add to his totals. He does need to do more of the post up in front of the net and smash rebounds/deflections during regular play, but I think you'll see that.
The question is still a matter of does he want to go for it?
One side note, it is quite ridiculous that we're talking about a player having a shot at that record. I don't think we will see that anytime again in our lifetimes, unless goal scoring goes up dramatically.