The truth is Ovechkin will not retire before 40, and some of the people who say he most likely will by 35, maybe just want him to.
If Ovechkin didn't really care too much about hockey he wouldn't be playing season-playoffs-wc every year. He loves playing and he will keep playing for as long as his heart is in the game
Considering the era were in, he is one of the toughest and most non-injury prone players of all time. He loves getting individual awards (even if he gives the standard answer like "awards are okay, but team blah blah"). Team awards are great, but being the best player or being the best at something is extremely rare.
No top players in any sport get to where they are without having an ego and wanting to be the best.
I expect Ovechkin to play until at least 41 or maybe 44 and if he gets close to 800 by 40, I can bet the farm he will try and break the goals record.