My father has my Dell mechanical keyboards. He agrees they're the best keyboards he has to type on, but he doesn't know why. (I never felt the need to explain.)
As to the feedback loop/echo chamber, just remember that there are certain types of keyboards that are easy to attain, and difficult to attain, whether you're on this forum or not. Pretty much everybody older than 27 has tried a BS keyboard in their life; and Das Keyboard (and subsequently the M10) and their availability on Amazon have brought Cherry MX blues into the general public. Less substantially, when the Matias Tactile Pro 2.0 was released, a lot of sites reviewed it in comparison to Unicomps. I don't know if that translated to any sort of surge or not though.
Point is, the market is partially responsible for the sampling of opinions in the first place. And the second point is, this forum is more diverse than the market.