I think the professional car builders get put off from forums by all the questions people ask on top of critiquing their work (if it's negative) . Its easier to just show your work on Instagram etc and get " # cool build" with no questions asked and show off your talent.
I love seeing the pro builds but when I see 6 questions that follow the builders posts like Mark Stielow , Ironworks etc I just shake my head. Those are car builders and car guys but to be overwhelmed with questions every time they get on the forums would be enough for me to stop posting on the forums to.
When I like something they do I try to do as much research as possible before bothering people.
There's a lot of shops that use to post on here that I haven't seen in awhile like JCG and Ironworks etc. Their build updates where always exciting to see and easy to follow and subscribe to on this forum.