Van Persie had a myriad of different injuries right through out his career, Kane has just had the one, although repeatedly and in both ankles. A fit Kane is no brainer no matter the cost but this isn't a fit Kane, it's a long way from the peak Kane, that was 3 years ago. This Kane doesn't physically dominate and bully defenders like he used to, he doesn't look to go in behind half as much as he did. He was like Shearer in his prime, now he's like a mixture of Lampard and late career Rooney. He will still score 30 goals a season but peak Kane would have scored 50 for this City side.
Another thing to note is it has been repeatedly stated Spurs rushed him back, that was Kane each and every time, chasing records. Fair enough we didn't stop him but will Pep if the player says he's fit? Hard to turn down guaranteed goals if the player says he's fit.