A while back, I watched a nearly-two-hour video about the history of Disney's various fast passes.
https://www.youtube.com/watch?v=9yjZpBq1XBEUnder the old system, Disneyland and Disney World had completely different fast pass mechanisms. The Disneyland fast pass worked somewhat similar to how you describe, but the Disney World fast pass allowed (and therefore effectively
required) booking of rides many days in advance of your visit. And Disney's resort sales arm would leverage this to give first dibs to those who book their hotel stays (etc.) through Disney Resorts. The upshot of this is that if you were visiting Disney World from out of state and tried to book a fast pass on your way to the park, you would find out that oops, you needed to book that ride two months ago. (The Disneyland system allowed same-day booking only.) This resulted in a pretty terrible experience for those who are not experienced Disney World goers and didn't know how to work the system.
The fast pass systems were suspended at all Disneyparks during COVID, and in winter 2021, Disney implemented the new two-tier fast pass "Lightning Lane" system for all US parks. Like most other theme parks (Six Flags, Universal, etc.), you can pay to upgrade your park ticket to Genie+ Lightning Lane, which allows you to reserve a spot at most (?) rides; one ride at a time, all day long. For certain premium (i.e. newer) rides, there is Individual Lightning Lane, where you pay to go in the fastpass line once.
Genie+ Lightning Lane and Individual Lightning Lane are completely separate; paying for a day-long Genie+ does not let you skip the line on a premium ride, and you don't need Genie+ to pay for and use the Individual Lightning Lane.
To be honest, Genie+ is how most competitors' theme parks already work. As for Individual Lightning Lane... enjoy capitalism, I guess. They wouldn't do it if people weren't willing to pay.
P.S. I know that Disney World changed their fast pass system several times, and the version you recall may have been one of the most recent implementations, changed to be more like Disneyland's old Max Pass. But there were a lot of complaints from customers under the old Disney World fast pass system.