I’m not sure about billiard popularity overall, but in my city we too have lost at least 5 dedicated pool halls in the last ten years (and only opened one new one). From what I’ve heard third-hand, most of them were doing okay, but just couldn’t afford the rent increases, and another one lost their liquor license for unrelated reasons.
Our leagues still seem to have all the same players we ever had, it’s just that now we’re stuck playing in pool rooms attached to bowling alleys and on little coin-op tables in bar corners. It stinks because we’re usually crammed into those places like sardines on league nights. And the bar boxes are a sorry replacement for a good nine-foot table.
It could be coincidence, but I noticed that the closing trend coincided with when our state passed laws making smoking indoors illegal (mostly). For some reason I’ve never understood, smoking and billiards have always gone hand in hand. Perhaps pool halls are hurting because people who just wanted to smoke and chill had to find other places to go?