Over the past 52 years that I have been in billiard rooms around the U.S. I can say there is one main reason that the rooms disappeared- they were not managed properly. In every pool boom that I experienced- over 80% of those opening rooms did so without really knowing what it takes to run a successful business.
Some of the biggest issues that I saw that contributed to the demise of most pool rooms included: absentee ownership, poor equipment maintenance, allowing the wrong element to dominate the room, not providing proper customer service to everyone that walked into the room, not building youth and league programs properly to assure continuous attendance beyond the casual and the hard nosed players, not holding tournaments with regularity, fairness, and/or concern for the average working person in terms of tournament times and hours, not balancing the room priorities between the real players and those that attended for social reasons- be it a bar/ music or just fun in general - so that all feel welcome and enjoy.
Most rooms that survived the 60s 70s and beyond or started in the late 80s to 90s and had a long run got many of these things right consistently- unfortunately that 10 to 15% was far too small a group. Fading interest in pool had a lot to do with the way most rooms have been managed - way more, I feel than just the fading interest from the latest pool movie. I hope if the resurgence that folks hope for does occur, that this next tier of room owners do a much better job of looking for longevity instead of the quick buck.