Generally speaking, one great use of framesets allowed for the "functional" separation of website navigation from content pages in a browser window. This greatly simplified content pages and website construction, as content pages only had content on them often times organized with simple tabular layouts. There were issues with this:
As a navigation link was clicked, web content was delivered in another frame, BUT the URL did not change as the "contents" of window changed. Thus, if you found those perfect red shoes in size 10, you had to grab a URL provided by the website developer from the page itself, because the URL in the address bar did not change with the content update. It was not a big deal at all, but it did require user education (like 10 seconds worth). There were others. You'll see those in other documents.
Why was this such a threat to Bill Gates ?
He was a software developer. Windows had been designed to be an operating system that allowed software developers to build applications. With web based software as opposed to PC based software, any old unix machine with any old web browser on it worked fine as a client. The windows based computer industry had no value. The concept of local networking, servers and PC's would become irrelevant in a matter of a few years. That's why.
This is the EXACT SAME type of threat the "cotten gin for hemp" posed to lumber land owners in the 1930s. With a few years all of their investments were to be valueless. They outlawed Hemp (Marijuanna) and we've been living that curse out ever since. This is the same story, just 70 years later.
To thwart this web based software threat, Bill and company made it impossible to see the mechanization in the browser. We had to program blind with very little feedback on errors. When you see what I was able to build blind, you can only imagine what could have been built with access to browser information as was provided by Google Chrome in 2008. They also started rumors that Classic ASP would become obsolete and that framesets were too. And yet, here we are 20 years later and both operate just fine, albeit the threats are all still out there.
Why would they all work just fine? Because that would be like making the tires on a car obsolete.
So why didn't everyone revert back in 2008 once Google Chrome was released?
An ideology about obsolescence had been seeded much like he seeded the fake viral stuff in 2020. And it had years in the make by the time 2006 came around. In addition, they had still not modified browsers to allow the manipulation of URLs in the address bar by the developer as new pages were called, thus that silly "url from the webpage" would have still needed to be used.
For clarity. There were and are a few aesthetic limitations with framesets that "creative types" found too limiting. Instead of allowing us to play with those as they toiled for 10x longer on complex sites would have been the appropriate thing do to. The problem with that? No one would have ever purchased their expensive work.
There are many facets to this. Bottom line -- a baby got thrown out with bath water -- and that toss has cost the US Gov't and US Corporations Trillions of Dollars. Great for "employment". Horrid for a society which had been prepping for, and trying to break through to a Golden Age for over 50 years.
We've all been robbed in Big Ways. This type of stuff doesn't happen "by accident". Big Thinkers think BIG. Dark Big Thinkers do too. Darth Vader comes to mind. They exist just like the rest of us. The winner has been cast in stone. Earth and the Animals win. The only question left is how many humans get to enjoy the space with them.