Browsing in the history of cue sports largely in Brunswick related archives and mentions, it actually seems like pool & billiards were pretty high end/respectable before 1930. Lincoln, Mark Twain, a number of "mega-church" & abolitionist preachers of the 1800's proselytized on the values and benefits of playing the games. The equipment was expensive and the target audience had wealth, taste, and education. Whatever their personal foibles and failures, they also were the arbiters of moral and cultural values of the times.
In 1929 the stock market crashed. As the 30's advanced pool halls became the default home for a jobless crowd of transients, often homeless & in fairly desperate circumstances. Family type people stayed away & lectures about pool halls being evil became more common. The war revived Brunswick's fortunes (pool tables for the troops), and afterwards they tried to revive the family consciousness aspects. But even for Brunswick, it was a hard uphill struggle, and they made more money from their other sports equipment conglomerates, and especially bowling.
With Brunswick's efforts, movies, TV (Mosconi & other pros and shows, etc) pool improved its interest through the 60's to become a relatively familiar/common & somewhat family related passtime and skill again. By the 70's there was so much drug money sloshing through the lower economy that almost non-stop action began to occur anywhere there was a pool table. Pools image began to drop, and the early late 70's/early 80's were a depression again. The few pool halls that had sprung up started to close again.
I don't think pool's image overall is that bad, and may depend where you live/shoot. When i started up again after a 25 year lapse, the regional VP of my local bank asked me for a regular Tuesday game. Then Wed. we'd both play in a regular tournament at a decent local bar that also held couples dance classes at the other end. From those beginnings, the pool scene grew to be pretty large in a town with 2 universities. Lot's of grad students & professionals play in the leagues. Still not large enough to support a pool hall (periodically the now retired banker considers it, but the metrics don't come close to working out).
Basically i agree with the OP's premise: seediness (or lack) does not have much to do with current cue sports popularity. Choices by the current demographic tiers, and hence economics do. Cost of real estate in popular areas probably makes a pool hall without a liquor license un-viable in just the areas that would have the best demographics. The pool halls that still exist tend to have a bunch of retired guys who "own" them and the tables. Have kids ever thought an enterprise populated with doddering old geezers was a cool activity?
smt