The reason companies fund the cost of producing a TV commercial and airing it is because it makes economic sense i.e. it pays off. The target population of pool players (that's people who spend money on equipment, not the number of people who would respond to the survey question: Do you play pool more than once a year) is pretty small and simply doesn't justify the cost in most cases.
The logical avenue to make a return on such an investment, is to advertise like golf equipment makers do, primarily on telecasts of the sporting event in question. There is hardly any televised pool, certainly it's miniscule compared to golf, which is on network television virtually every weekend. Adding to that, a high percentage of golfers like to watch their game on TV. Generally speaking, even serious pool players do not care to watch pool on TV. It would make little sense for a billiard company to advertise outside the game, like on network prime time programming, because it's too much money to reach too small a target. Simply inefficient.
The fact of the matter (meaning my opinion, lol) is that as a group pool players are a bunch of nits that don't spend money compared to say, those who play golf. That's why in addition to Callaway and Titleist, advertisers such as Mercedes and Pacific Life flock to advertise on golf telecasts. Add to that pool is not perceived as technology sensitive like golf, where many people run out to buy the latest driver every time one comes out. And the few pieces of equipment that aren't durable goods, like chalk and tips, are cheap.