Because his contract sets and/or will set the market for the most elite players in the league. Though there is a contract max it has almost never been in play as a real bar for agents/players. McDavid getting the max means that the next time the truly elite players are due for contracts they will use his hypothetical max or near-max contract as the measure of their value (likely as a percentage as the cap increases). If those salaries go up, the PA is happy because it sets higher bars for things like arbitration, qualifying offers, etc as well.
But what incentive does the PA have that McDavid get's more of the fixed pool of $$$ than Derek Ryan? All of the money will be spent on players that they represent. The PA's dues/fees etc will not change.
The PA wants all players to sign for as much as possible, so the owners can't come back later and suggest less money go to the players in future CBA's based off of the star players taking xx amount.
Obviously I'm not in the room, but I don't see how owners would use that as an argument... how does it logically even flow? "Oh well the top player(s) in the league only make X, so surely we don't need to increase the players' revenue percentage from 50% to 52%."
If anything, the league would probably rather top-end salaries are constrained a bit for the simple fact that it's not the entry level players that get squeezed... there is always another hungry NHL-wannabe ready to take league min and fill out a roster. The players that get squeezed are the aging stars... Thortons, Marleaus, Getzlafs... who have banked plenty of coin and when the salary starts to get squeezed... it's no longer worth the risk to their health/time away from family. The league would obviously love the household names to stick around as long as possible because they are: a) still talented, b) drive gate revenues still and c) nostalgia.
In any case... I suspect the negotiations around revenue sharing are entirely based on established metrics from other leagues. NHL is 50%, NBA is 49%, NFL is 47%... hard to see these numbers moving too much. So the bigger negotiating points are probably around player mobility, player autonomy, and initiatives to grow the pie.
You're still not getting it. It's a fixed pot. The PA doesn't get more or less because McDavid or anyone else takes more or less. That's not how it works.
Exactly.