SMT
No, I don't claim to have intimate knowledge of the golf business. However, recalling the component landscape back in the early to mid 2000's, we not only had several brands like Bang, SMT, Alpha, Wishon, Ashton, TourSwing, Zero Tolerance, Nakashima, Purefit, KZG, etc. making heads, but most of them were releasing new models fairly often (especially as driver head sizes increased from 350cc to 400cc to 460cc). And there was a lot of buzz on the forums with each new model. That landscape has changed drastically, and much more so compared to what the big majors have been doing. I don't think it's a huge stretch to presume a greater % of these smaller companies (as well as smaller OEMs) decided they could not compete in a golf equipment industry that, as you said, sucks.
