80+% of the plane is Y.

Treating these people like they're on Ryanair will drive them to airlines that offer an equal or better product at a lower price. No US airline offers a worse Y product than United, other than Sprit.

On the richer side of the equation, UA offers a worse domestic F product (where they offer it) than every other major.

DL recognizes that people like "Cool", people like entertainment, etc. They are worried about losing passengers to Virgin and JetBlue, not United.