So you mean football needs a situation with Mbappé not being bothered for honoring his contract so Kane doesn't have to honor his? How does it make sense, his situation is the opposit.
On top of that, Mbappé is threatening to leave the club since 2019, he has zero credibility when he's trying to act like a good little soldier who wants to finish his contract. I'm not saying PSG isn't to blame because they're obviously trying to strong-arm him but he's the one that started this whole PR circus years ago with public threats at very inappropriate moments.
He's threatened to leave the club and the club have previously priced him out of a move. Tables have turned in this case. The club offered him the loyalty bonus, he accepted and signed. He plans to collect it next season after being loyal to PSG by staying. He's keeping to his end of the contract. All Mbappe essentially did was insinuate that he wouldn't be staying after next season. We've seen clubs tell player during a season that they are going to be sold or their contracts aren't going to be renewed. Yet we expect those players to honor their contract despite feeling poorly about it. Here PSG have had the tables turned on them and they can't seem to accept it without venting to every media outlet.
Kane has also been trying to leave for the past few seasons and has also been priced out of a deal by Spurs. It's similar in that sense. Unlike Mbappe, Kane signed a longer term extension and has now had to deal with being overpriced to every team Spurs have negotiated with. I would argue, knowing that he would like to move in future, Kane should have done what Mbappe did, take a shorter term contract and have the option to move for free when the contract expires.
I've seen clubs marginalize, bench and punish players for choosing not to sign contracts that will determine their future, with media outlets consistently supporting these clubs because "players are already millionaires", not truly appreciating that clubs are billion dollar entities. Players due to trying to appease fans of the teams they've played with have often succombed to a disadvantage in these situations with clubs, where the clubs are open to using media outlets to push negative stories about these players. I've often heard people call players greedy, but never put attention to clubs in these circumstances. Now due to these clubs like Napoli, Tottenham and their like pricing players out of moves to desired locations ( after some have previously made promises), the players are now making a choice to see out their contracts. This summer, so many older players did not receive new contracts, the players didn't hold them to ransom, threaten not to play or verbal abuse the club to media outlets. So PSG need to behave themselves, honour the contract that was signed and accept the fact that Mbappe will be leaving next season