When Zion Williamson of Duke went down with a severed shoe and a sprained knee 30 seconds into Wednesday night’s showdown with North Carolina, it was bad news for plenty involved. Williamson now has to deal with an injury. Duke had to play its archrival without its best player and duly lost, 88-72. Nike faced questions about its product’s apparent failure.

But ESPN, broadcasting the contest as part of its multibillion-dollar deal with the Atlantic Coast Conference, did just fine. The game’s biggest star was injured for nearly 99 percent of the game, yet on Thursday, the network reported that the rivalry had produced its highest-ever ratings for a weeknight college basketball game.

The episode crystallized the economic limitations that N.C.A.A. amateurism and N.B.A. rules impose on Williamson, a preternatural talent, and the unique ways that they limit the income of a unique player.

If the N.B.A. did not bar high schoolers from heading straight to the league — a rule that may disappear in a few years — then Williamson could already have been playing for, say, the Atlanta Hawks and making several million dollars on his rookie contract. If N.C.A.A. rules did not prevent players from signing endorsements, Williamson could already have been receiving millions from Nike.