I don't see how anyone can say keeping De Gea isn't worth 20m. Rooney makes more than 20m a year, and he's was less important to the team last season.
Yeah, goalkeepers generally make less, **** knows why, its the most important position far as I'm concerned. The point is its not unusual for top clubs to throw 20m a year for their best player. De Gea is second only to Neuer, you just can't replace its always a risk having to replace that kind of quality. With an unbalanced team, its a no brainer to try and keep him unless he forces a transfer.
And who knows, maybe his GF dumps hin next year and he'll stay.