Patrick Kane is 29 and on the most expensive contract in the league.
Elite talent, but the price isn't going to be as high as his stature deserves.
Exactly. He's making 13 and 12 the next two seasons before his salary drops a bit for the close of the deal. Chicago absolutely needs cap space --- but there's no need to sell the farm for him. Chicago can demand all they want, they're not clearing 13 million just on one team. They're taking a contract/someone to insert into the lineup and keep contending for a Cup, and 2 others (pick and young talent).
For example: Kane for Kane + 8 + Nylander or Reinhart (never both). At the most. I'd even push for that 8 to be our highest second. Taking PKane and 13/12M means no defensive upgrade and losing Reinhart next season. We'd be paying O'Reilly, Eichel, and PKane's more than Pittsburgh pays Crosby, Malkin, and Kessel.