You'd have loved trying it pre-Web :-) I was a product manager in the late 80s/90s and I needed to do competitive analysis for pricing and feature prioritization.
One of our sources of information was an analyst firm that basically collected faxes of product briefs from ourselves and everyone else and then basically charged us large sums of money to send us copies of the product briefs for relevant products because we couldn't ask for them directly.
There was another firm that shipped us basically their own datasheets in a standard format of the products in a space (computer systems), which were often considerably outdated/inaccurate.
I sometimes say if I had to go back to those days, I'd quit in a week as I basically wouldn't have the information to do my job.
I've only worked at one company that really went all-out on this. Samples were bought of competitive products, tear-downs and estimates on manufacturing cost, use of ICE-machines (where practical) to understand the underlying software to some extent. All in addition to studying usage, manuals, etc. Mid 1980's.
I think it was really useful, but then they also had a QA department that was a peer to and practically as large as engineering.
Certainly there were computer mag reviews of products and I'm honestly somewhat split on the transition from "expert" and theoretically unbiased reviews to a much more heavily crowdsourced set of reviewers. Not sure I'd call modern online crowdsourced reviews "magical."
Thanks for reading!
Thanks for reading!