I was one of the original reviewers for the website Armorama. At first I reviewed new kits I had just bought and built (back in 2002). Eventually, I started getting kits sent directly to me from distributors and manufacturers and eventually when the site started getting review samples sent to them, they were passed on to me (as well as other volunteer reviewers).
It was a nice gig until your hobby becomes work. It becomes a pain to have to stop building to take photos, keep notes, etc. Then there's the "rush" to be the first site with the review of the latest, highly anticipated hot kit.
I have spent a quarter century on actual modern US armor and was comfortable as a knowledgeable modeler (I dislike the term expert) on many of the kits from this genre, but when they start sending me panzers and other stuff that I could review as a modeler, but not as a subject matter expert, I started to lose interest.
Your reviews end up getting nitpicked by guys who, for whatever reason, have to take shots at you. You'll see comments like "How can you rate that kit as an accurate model?? The road wheels only have 34 bolts and not the proper late war 36 bolt road wheels!!" Of course, these guys NEVER write reviews, they just nitpick others.
Bottom line, if you want to end up on one of these lists, you must first be one of the volunteers who write their own reviews of kits you've bought, submit those to the various websites (none of these non-profit model sites would turn away well written reviews) or to the various club journals like IPMS or AMPS's Boresite.
Eventually, if your reviews are well received, you'll end up on the list of guys who get asked to do reviews.