The problem with pool is not the size of the viewing audience they have, but the size of the viewing audience they don't have. Think of an average Sunday at the Masters or any Sunday with the NFL. In order to financially sustain any endeavor, you've got to have REAL big numbers. A couple of hundred thousand here and a couple of hundred thousand there just aren't enough. It takes millions!
Why can't Big Pool acquire the kind of sponsors that one Nascar team can? Why doesn't Big Pool attract glamorous spokesmen? One of the many problems with Big Pool is that it's just not very pretty. Do you want to watch the sun-tanned gladiators on the fairways and greens of Pebble Beach, or a dark room full of fat guys with tattoos? If you are an upwardly mobile family, do you want your kids playing on the golf team at Wake Forest, or downstairs at Nick's Pool and Pizza?
The investors and sponsors of this world like Pretty People out in the Sun. That's where the money is.
So, what's the solution? How do we change a dark, often foreboding image that has had a hundred years to manifest and nurture itself? I don't know the answer to that. I just know that what we have now isn't working. But Big Pool knows that, too. They're not dumb. They're just like the rest of us poor suckers, trying to scratch out a living in a cold, hard world. Sadly, it's just a very small world. Just very small.
Pool hasn't been a "top" sport since the invention of television for all the reasons you mention. But the good news is that it should be able to survive well enough as a niche sport as it has a global following (Europe, China, and US) with a dedicated but small core customer base.