Why no reviews of the Magnepan 3.7 in Stereophile

Reviews are like drugs. You know that they are no good for you but you read them anyway....

The 3.7 is an interesting speaker. Listening to one the other day I was very pleased with the soundstage, localisation and resolution of the reproduction. I was less impressed by the bass which did not dive very low at all and was quite lean. Careful matching of amplification is needed because if the wrong product is used the treble is too hot.

Reviews are mostly of little value, they always leave cryptic passages that leave them plenty of wiggle room if called out on a review mistake. On top of that unless you use same amp, source, wire, power, room, placement and dare I say bias towards or against a product all reviews are a waste of time. Reviews can entertain and give some valid info but the review only serves to enrich the reviewers system, sure they have to "suffer" through reviews (all the while trying to convince us how hard it is and how bad they have it) but show many any reviewer and I will show you how that "suffering" paid off big time for his personal gain.
So read the reviews, get what you can from them but know they are worthless to most everyone except the company and the reviewers system.

But all this begs the question: Why does Stereophile need (implied) consent from the manufacturer, in the form of loaning the speakers, before reviewing a speaker? Why not just go to a store and buy, or borrow, a pair? Consumer Reports does not wait for car manufacturers to give them a sample; they buy one at a store, like a consumer would.

I don't know, I find many reviews do a pretty dark good job of describing the nature of the piece equipment, for the most part I have found reviewers do pretty good job of describing the basic attributes - given that we all know the importance of associated equipment and the speaker placement within a room. I give them more credit than you do, though as always with a grain of salt, but a good reference point for considering a product. And of course, some reviewers are a lot better and more dependable than others.

"What is better marketing - a good subjective review with a couple of questionable artifacts in measurements, or no review at all?"

No review at all, I have passed on a few auditions because of bad measurements. Measurements are not everything, not by a long shot but if you listen to enough speakers and also analyze their measurements you can correlate the two with what you like and do not like.