Most bars don't care, nor could many employees explain the right rules. They've already got their hands full with orders, drinkers, etc. Some pool halls may be able to help, but half of the people out there couldn't give helpful advice if their lives depended on it.
Sorry, man, but I really don't see anything more than.. "this is what they should do and it would be awesome." There's nothing of substance to explain how it could happen, how it could be sustainable and why it would benefit all involved. Once you have to balance out the bottom line, it changes a lot.
Look around at your next league night. From what I've seen, the A and AA players more often than not are drinking iced tea, water or cheap beer. Maybe it is so they can keep clear heads or maybe its just because they are in a pool bar 6 nights a week and it's too expensive to drink the good stuff. Maybe both. Look at the beginners. They're there to have fun. They order doubles, and good beer and fries because what the hell, it's their fun pool night. If they do come in on a non-league night there's a good chance they will bring a friend or two and they will all drink beer and miss shots while ordering food, etc. For bars, beginners mean a whole new crop of customers. Certainly enough to justify an additional investment in equipment or training for staff.
If pool halls that didn't serve alcohol catered to families and a larger audience they'd find their tables busy on hours they normally expected to be dead.
Distance races learned years ago that having the race expo the day before the event got a ton of people both participants and their family and friends to come buy stuff. Race expos have guest speakers, autograph areas, huge merchant demo areas where people can try out new products. Pool tournaments have it even better. With a captive audience between games they are definitely not making the most of that time. Other than Las Vegas, which tournaments cater to the manufacturers that way? Not many. Why? There simply aren't enough people. If pool spends more time appealing to beginners they will find more of those people showing up to watch tournaments providing a large consumer base for products.
I could keep going but at some point either you see how new money spends easier than old money or you don't. Its an area I have experienced first hand in other areas and until proven wrong I don't see how pool couldn't benefit from the same marketing strategies employed by other industries.