I think we're going to see players playing into their mid to late thirties more frequently over the next decade. Elite players are pushing the age boundaries more and more helped by the latest tech, nutrition and fitness regimes. I think Modric was 32 when he won the Ballon d'or and at 36 he's still putting in some sublime shifts. Karim Benzema looks a shoe in for that same title this year of 'best player in the world' and he's 34. We've got Ronaldo, Messi, Ibrahimovic, Bale, Lewandowski (who is, at 33, looking for a move to Barcelona) the list goes on.
Players that don't rely on explosive pace alone (which is usually the cause of injuries and niggles down the line) have proven that, at 30, you may not have even peaked yet.
Kane will be banging them in at spurs till he's 40.