The "how many reviews it got" rule

It's akin to writing a reference letter or a letter of recommendation. If a student asks me for one and I have negative things to say, I'll pass on writing the letter rather than writing a negative letter. If I really have to write one, I'll couch it in generic terms that admissions can plainly decipher, but that don't openly condemn.
Reviews strike me the same. Every now and then Stereophile will write negative things about a unit, and the company then immediately rebuts those critiques in the back of the issue, usually pointing out detriments of the review or set-up or something like that. But I can't remember Stereophile or TAS ever ending a pages-long review, complete with sexy photos and graphs, with something like, "Don't buy this. It sucks. You'll regret it."

^^^^^
True. I can't speak for anyone else, but I have to remind myself every now and then that just because a particular component doesn't make a "Recommended Components" listing doesn't mean it can't hang with the ones that did. Perhaps it just didn't get reviewed.

There are myriad manufacturers out there and a finite amount of review space. Especially review space by knowledgeable and articulate writers.

There are so many good component manufacturers that get little press/reviews. Some out of choice; others out of circumstance.

Take von Schweikert speakers or Daedalus speakers. Beautifully made and beautifully sounding speakers that rarely, if ever, make Stereophile - though do appear in Dagogo and other fringe publications.

Or Decware amps and speakers - which refuse to be reviewed by anyone except customers - and that informally.