Why can't they just name the rosters without actually having a game?
I can name that song in one note. (Who else is old enough to get the reference).
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While the pro bowl has lower TV viewership than many other games, some people do watch it, the network that broadcasts it pays the NFL and sells ads. The game sells out. Those tickets are revenue. Many are tickets that are won, but the prize giver paid for them. Also merchandise NFL sells pro bowl jerseys, not quite as exciting as owning a super bowl jersey but still people buy them. The game isn't as exciting as the week before or the week after but the NFL makes money.