There was a considerable amount of overlap between the browser and the file manager originally. The notion of the modern day internet wasn't really here, and instead a lot of companies saw "browsing the web" as mostly equivalent to "browsing your files - but remotely".
Even Microsoft did this - "Windows Explorer" (The file manager) and "Internet Explorer" (The browser) shared a huge amount of code. To that point that I could still write COM browser helper objects that run in both of those programs as late as 2018 - only stopping when MS finally killed IE in favor of Edge-Chromium.
Basically - Back then the web was just files to be browsed, and that was the job of the file manager, and people correctly identified that the web had monetization opportunities. They were just bad at identifying exactly what they were.
File management was a key activity at that time.
*http://toastytech.com/guis/chicago4.html
I guess they figured it would be more profitable to sell that as a standalone product in the office suite.
And famously got sued for closely tying the browser with the OS, despite the design making technological sense.
Well, there are Total Commander and other commercial file managers: https://en.wikipedia.org/wiki/Comparison_of_file_managers
We'd (sadly) call that Facebook nowadays.-
Right, at the time...
It's still like that today, you build something attractive to users and assume you'll figure out the monetization later. It was more of a wild west back then because they were throwing everything at the wall to see what would stick since everything was still too new to guess at what would work though.