Mainstream reviews-why so few?

I think buzz creates the demand for reviews, and buzz is created from advertising and shows, and big companies have lot's of money for advertising and shows so that is likely the reason. I rarely believe in conspiracy theories, except Roswell of course but we all see the improvement in sound equipment once the alien technology was examined and shared with the electronics industry.....

I own the GMA Europas, and I think they're great, but I would certainly like to see the measurements on them (frequency response, step response, phase response, waterfall). I wish GMA was a little forthcoming with measurements. I like their products, but their new website is a bit too slick and technobabble for me.

One thing that I think does speak positively for GMA's products is that you don't often see them for sale in the used section here on Audiogon.

I think manufacturers have to agree to certain things like long term (almost open ended) loans to reviewers, no preview of review, keeping some distance after item has been set up and verified to be working properly, etc. I knew a speaker manufacturer about 15+ years ago who refused to do these things (he really wanted to stay in touch with the magazine on a regular basis and know what the reviewer was thinking all along). He got only one review, which was positive, but ended up pissing off the mags with what they claimed was his "butting in" too much.

Twas always thus. One hand washes the other. It is convenient to rely on cliches as I have just done but it also disingenuous to dismiss any and all suggestions of misbehavior as conspiracy theory. There are systems of graft at play everywhere we look today and it certainly isn't difficult to draw certain conclusions about the way we see the review process plied.
Green Mountain Audio has been producing exceptional product for nearly 30 years under one name or another and has spent most of that time in the shadow of lesser products with better connections. His neighbor Jeff Rowland has been harder to overlook but he too has been largely ignored in the same way.
Some years ago I was affiliated with a small company that made one product only but it was one of the best engineered and packaged products available then. The Timbre Technology TT-1 Dac was submitted to the Absolute Sound for review. They assigned it to Jonathon Valin. He jumped ship and went to Stereophile taking the Timbre with him. He subsequently gave it a rave review in that magazine but, unfortunately, was trumped by Robert Harley when he was the resident expert. Harley at the time was promoting any and everything offered by Sonic Frontiers and Timbre became the victim of his overriding faint praise. That began the end for Timbre even though it was arguably one of the very best DACs on the market at that time. The company struggled for about 3 more years but ultimately had to give up the ghost. Many small manufacturers are aware of this or another similar tale and scrupulously avoid submitting themselves to that potential abuse.
It's a big gamble that can make or break you. Unless you have the money to encourage praise of your product, you will likely be relegated to obscurity or otherwise abused. Ad money works in audio like campaign contributions in politics.

" They assigned it to Jonathon Valin. He jumped ship and went to Stereophile taking the Timbre with him." Really? I doubt it.

Kal