I don't think those people ever used the standby line, it was Fastpass or nothing based on what many have shared.
I think so much has become confused in the arguing about how many fp's people used to use. Honestly, I think it all depended on party size, ages of those in the party, experience with WDW vacations and, obviously, the park. I really only think it matters for MK.
For example, when I was a kid and travelled with my family of five, we barely got anything done and used maybe 2-3 fp's at most. It was my parents, myself and my younger sisters.
We ranged in age from 4-12 during those years. We were way more interested in characters, table meals and browsing souvenir shops than riding as many rides as possible. We also moved slowly because of my younger sisters. We were new to Disney and not seasoned as far as maximizing our time. I think this entire scenario can be said for many visitors as first timers and families are the majority of WDW vacationers.
On the other hand, I started visiting with my BF in 2012. We had both been to WDW several times and knew how to navigate the parks. I did a lot of research to brush up on my knowledge and had a very set schedule so we could maximize our time. We also are mostly at CS because we were on a budget.
We move quick when we visit, and we ride many, many rides at MK. Here is what I can recall us doing from our most recent trip because I can remember basically what we were able to accomplish ride-wise:
MK FPs: BTMRR (2), Pooh (1 Bf/2 me), Peter Pan, Buzz (2), Splash/Space (only for bf-2), Barnstormer (1 bf/ 2 me), Mermaid
MK SB: BTMRR (2), IASW, Phillharmagic, various character meets, HM, POTC, Aladdin, Tea Cups, MI laugh floor, Carousel, COP, TTA
Yes, we rode Thunder 4x! We rode 3x on other trips, so that's not a stretch. Anyway, that just goes to show that two able-bodied 20 something's can get 12 FPs and ride almost 25 rides in one day. However, when I was younger we would barely do a tenth of that. It really depends on the party size, age and how much experience you have at WDW.
Also, I think this only matters for MK as I said. For the others I don't see why anyone would need more than three (or two really).
That was way longer than I intended it to be. Whoopsies......
