The way it works is a Dustin Martin type situation with Puma.If WCE were a stock then Harley Reid leaving would cause all shareholders (sponsors) to lose big money.
Harley Reid brings eyeballs which means sponsors get more eyeballs. Shareholders (Sponsors) would dip their hand in pocket to help keep him. A few million out of the pocket of sponsors is nothing compared to the eyeballs Harley will bring to sponsors.
To further explain this theory what's more legit
1. Sponsors pressure WCE to keep Harley (good luck try to force the richest club to do that)
2. Sponsor chipping in to help Harley stay
The player managers work with club sponsors on those endorsements, and the club just helps make those connections.
It's another way of leveraging the club outside of the cap to get a player's financial deal up without it costing money in the cap.
But he'd get those deals anywhere, so he's very likely not going to leave just for money. If he leaves it will be a lifestyle/location type decision, or a success/opportunity type decision, e.g. he might leave to a contender if he felt he wasn't going to win a flag at the Eagles or he might leave for a new challenge if he did achieve success at the Eagles.