I get the reluctance Levy would have to sell to Arsenal (not that they'd bid 100 million) or Chelsea (not that Kane would move here) but is the relationship with Manchester United really so bad? Surely he has a pragmatic side to him.
The relationship with all the rivals is that way now.
We won't sell to rivals, it's that simple. The Berbatov fiasco changed a whole bunch of things at the club.
Firstly, players and agents both know when they come here that they can't use us as a stepping ladder to Arsenal, City, Chelsea, United, whoever.
The best bet would be to run out your contract...except Levy doesn't allow that either. He now always holds contract leverage.
If you want to agitate for a move have fun sitting in the stands for 3 or 4 years because that's where your contract is. You can't really agitate the other players either because they wouldn't be happy you want to go to a rival (one of the bonuses of having both an English and local spine) either AND they're fully aware it's not club policy to sell to rivals.
Now if a player wants to move so badly then fine you have to go abroad. If you're good enough to attract rival interest then you'll attract interest from abroad as well and Levy has shown he'll accept less money to ensure that's what happens.
We've seen this happen. The last time we sold to a rival was nearly ten years ago. We've had players our rival clubs would want in those years in between and yet exactly none of them have ever ended up there.
Furthermore you can expect no moves to happen while Levy is negotiating for Stadium Naming Rights, Shirt Sponsors, and a New kit deal which all come up soon. These young stars like Kane and Alli are terrific for promotion and are how Levy will make a huge chunk of his money on those deals. Even from a purely monetary standpoint keeping them is more valuable than selling them for even the most ludicrous of transfer fees.