Do you disagree with the premise that centers get paid a premium over a similar-scoring wingers? Or that Hayes' value becomes diminished if he's a winger? We are talking about him possibly moving to wing as soon as next year here, the 2nd year of a 7-year contract.
Ultimately the issue isn't about what Hayes makes compared to people signed 3-4 years ago. It's about what he makes compared to what people will be signing for 3-4-5-6-7 years from now.
When players like Crosby or Giroux or Bergeron or Kane sign their contracts, teams are generally buying out a year or two of UFA time and make them (among) the very highest paid players in the game. But these deals work out to be bargains in the long run because they're still great players 7 years later.
This is how the aging curve works in hockey. There are exceptions, but the best players age better than other players. This has basically always been true, going back to Gordie Howe at least. The main reason is probably hockey IQ, which doesn't diminish. But it's also usually because they have a certain skill that doesn't diminish with age, or that it's so far in the stratosphere that if they lose a bit they're still better than 99% of the hockey world. Think of Jaromir Jagr protecting the puck, Sid Crosby stick-handling and passing/shooting off his backhand, or Chara boxing people out and his incredible reach.
Hayes doesn't have that. He's big, and that won't go away, but his skills are basically a little above average in a lot of areas.
The second-tier free agents don't age as well. We know they don't, there's insurmountable evidence. These players,while making a bit less than the top stars, tend to be overpriced by the middle of their contracts, if not total albatrosses. Like half the league has a guy like this: Lucic, Okposo, Eriksson, Callahan, Backes, etc.
I mean I know you know these things, because you used to argue against signings like this.