Why aren't high-end reviewers paid well? Supply and demand. There are hundreds of guys standing in line who would love to do the job for the access to the gear and the industry and the bit of notoriety it would bring them in the hobby. We are enthusiasts. Many would do it enthusiastically, and for free. And judging by many of the reviews I've read, pro-level writing is not a requirement for many of the online pubs.
Tim
Tim