Unfortunately AnandTech does not make its articles, also available in a paid subscription magazine format like PC Magazine or PC World. Otherwise you would have a lot of people here, half of them taking part in discussions, and the other half in support forum arguing about some issue they have with their subscription service or never received issues/volumes.
AnandTech is not for profit, although I am not sure if that also pertains to Purch who owns AnandTech. AnandTech runs of ads on their webpages.
the other reason is that not everyone knows that there is a website called AnandTech. Everyone knows about the magazines, PC Magazine or PC World, because people see others reading those physical magazines or even because there are ads for those magazines. Another way AnandTech is different from those, is that they give out awards, which is sometimes acknowledged about in very well known newspapers, and the winners of those awards sometimes even brag about the award on their own product advertisements. From what I can remember, I never heard in any advertisement in my memory of a award given by AnandTech being bragged about. I am not sure if AnandTech does give out awards.