although question is addressed not to me, let me just comment what I know for fact, from well reliable sources: as I know, there are no people in Thailand who does beetles breeding as a full time activity and the only main source of income. just now I returned back home after chit-chatting with my friend, who does insect business already min 18 years, and recently got interested in this new business option. he is still quite reluctant to start this in full, and the main reason he told me is : "the demand is not so high ... "
so, I think what timestamp actually means by saying "professionals" is actually - that members of that Forum (and there are several other Forums) already have a lot of experience and success in breeding beetles on a professional level. they surely do some trade and exchange - but as I know so far this business is not as developed as say in Japan or Taiwan. although some individuals (as Mr. Pisuth in Bangkok, author of book "Beetles of Thailan" and newer book especially on breeding - but only in Thai - and his son in Chiang Mai, who now takes care of the "Insect Zoo" there - see their website which has posts both in Engl and in Thai, although their Forum is only in Thai) are making consistent efforts in promoting beetles as pets, as well as started to sell some accessories, as substrate, decayed wood, larvae, etc. yet still, as I know, there is no any single shop in Bangkok which might have all the variety of tools, food, boxes etc. for beetles breeding - as for example in Taiwan and Japan. in comparison, there are so many shops in Bangkok selling all such things for other pets as fishes, reptiles, cats, dogs etc. however there is only 1 single shop which sells only adult beetles, no any other things for their breeding.