There were, and still are, a number of magazines in the electronics industry, EDN, for example, that were available for free to engineers that were 75% ads with a few articles. The publishers and advertisers expected the articles to draw the engineers who would be the ones to spec components for their current designs.
EDN - Voice of the Engineer https://www.edn.com Electronic Design News (EDN) is an electronics community for engineers, by engineers. Find the latest articles, magazines, tools, and blogs in the industry.
I like their tear downs of electronic equipment. https://www.edn.com/category/design/under-the-hood-teardown/...
Sadly Internet archive does not have a complete collection of old EDN magazines ....