It’s only a further 3 years from what I’ve seen, so he’ll be able to rinse the interested parties when he’s 26 anyway. Plenty of time to play for another club. A combination of ridiculous money offered, unfinished business with the club regarding the CL and the current state of La Liga finances at the big clubs and the knock on effect of that have led him to signing a new contract.
That and the owners threatened to butcher his family pets if he didn’t sign.