I don't know why a cuemaker would want to post on a pool forum. I would think they would post on a cuemaking forum.
That leaves what you refer to as "professional players".
The large percentage of "pro players" are unemployed bums who are basically parasites on society. Why would they want to post on a forum where they will, sooner or later, be told exactly that?
What are they going to contribute? Are they going to explain how to go out a restaurants bathroom window to skip out on a bill? Or maybe how to sell their cue to 5 different people and skip town with the money and the cue?
Most all of the so-called pros have done many wrong things to people around this country and they know that many of their "victims" post here and will eventually call them on their misdeeds.
Why open the can of worms if it's not needed? Not many of the pros have anything to gain by posting here so why do it? Gaining is their entire motivation in life, for most of them.
Think about if Buddy Hall was a posting member. He would have to talk about the 1991 COC tourney for 6 months straight.
Shane would be grilled on his theft of a ball from Morra at the 2012 Bankpool finals.
The top pros who've dumped and have strong reputations for being dumpers would be asked about it endlessly. They aren't going to subject themselves to that grilling when they have nothing to gain from it.
Even Shannon Daulton, who is generally regarded as a "good guy" in the pool world was knocked hours after a "welcome SD" thread was started on the 1pocket forum http://www.onepocket.org/forum/showthread.php?t=4581
ONB