I think Kane's situation is the same as Mbappe's, both players want to leave but their clubs are holding them back by giving new contracts and increased salaries. But yes, that situation has been around for a long time I think from the previous few seasons as well and as such, it would be a loss for the club itself if the player is not willing to sign the new contract on offer. So yes, if Bayern Munich can still give $70 million then I think it remains a good advantage for Tottenham too, but if Tottenham are too greedy then of course the money remains a big obstacle for Kane to leave.
Clubs hold players like Kane or Mbappe because these two players still have ongoing contracts so decisions still belong to the full rights of the club itself but when the contract expires and the player doesn't want to agree to an extension then it will be a loss for the club because they can't make money from other club transfer offers that want the player.
Bayern Munich are still on their last bid and are unwilling to renew bids for Tottenham to let Kane go but it is also true that Tottenham are keeping Kane at a high price considering Kane has been one of their mainstay players.