Warning: obnoxiously long analytical post...
Users here got me thinking about capacity and what percentage of guests can get on a ride. My intuition is that there was an effort to design rides such that every visiting guest would be able to ride, until around the nineties.
I'll specify what I mean when I say that "every guest is able to ride." I mean that on average day, all guests who meet the criteria for going on an attraction will be able to ride each ride at least once. Most of my data points I'll look at are going to be rides without any height restrictions, though some of these rides might be inappropriate for smaller kids.
So let's go back to 1967. An exciting year for Disneyland. New Tomorrowland debuts hot off the heels of New Orleans Square. Rides from the World's Fair are freshly imported. Pirates of the Caribbean makes its maiden voyage, and Haunted Mansion will be opening soon.
The park sees 7.8 million guests this year, breaking last year's attendance by over a million. Park's operate, on average, 12 hours judging by old photos of the glamorous roadside sign. If it's the off season and you want to visit Disneyland on a Monday or Tuesday, you'll have to go to Knott's instead. Let's say Disneyland's open 300 days this year. That's assuming basically that half the year is off season (5 day operation) and half the year is on season (7 days of operation). That puts us at an average attendance of 26,000 guests.
Now back to the idea of "every guest is able to ride." We're aiming for all these new attractions to have high capacity to reach the demand. Luckily, they learned a lot from the World's Fair where they had even more guests to service. The systems developed there, as well as the attractions themselves, are brought over en masse in just a few years.
Courtesy and efficiency are two keys that lean into one another. It's courteous ensure every single guest can ride every single attraction at least once if they so pleased. So they'll need a capacity to match our average 12 hour day that sees 26,000 guests.
They're basically freebies, but I'll start out with two of the World's Fair imports. First I'll give the theoretical hour capacity, then how much that adds up to on a 12 hour day.
Small World: 2,500/hr ==> 30,000/day
Carousel of Progress: 4,200/hr ==> 50,400/day
Moving onto some other attractions that open within a couple years of 1967.
Pirates of the Caribbean: 2,500/hr ==>30,000/day
Haunted Mansion: 2400/hr ==> 28,800/day
People Mover: 4,885/hr ==> 58,620/day
Over the next decade, attendance surges, while operating hours are expanded. We get the Country Bear Jamboree from WDW, but WED decides to include two theaters to double whatever capacity the original version had. Space Mountain is also improved when it moves to the West and is upgraded to a capacity of 2200/hr. Big Thunder Mountain can allegedly see 2,400/hr.
Now, I'll say the obvious caveats. The numbers are theoretical. And I found them online. But I erred on the lower end when I got conflicting numbers. You can see the rides are designed to have the capacity to service every eligible guest. The two roller coasters that debuted nearly back to back each have impressive capacities in their own right. Numbers are fuzzier here because we don't know how many guests are able to or want to ride these thrill rides, but it seems where still in the realm of being courteous.
Then... something happens. It's a slow trend, but there's signs. Disney buys a log flume from Arrow and makes no evident attempts to increase capacity over one's you'd find at regional parks. It can handle 1,500 guests per hour. The same animals once entertained 4,200 guests/hr in Tomorrowland. The theater sits empty. There's less of a compromise between razzle dazzle and capacity. Indiana Jones Adventure has a respectable 2,400/hr capacity (probably high, but I'm being generous where it hurts my argument), although that's not going to be enough to meet the demands of those rising attendance numbers. Plus, it's opening is paired with the closure of the Skway Buckets to save on operating costs. It's a new phenomena. There's no real net gain of attractions, and the new rides have even worse capacities than the ones from the 60's.
How does that work? Are those capacities just something that come with flashier ride systems? Would it have been possible to engineer a version of Indiana Jones Adventure that made some concessions to allow more guests to ride? Sure, those old rides were cocktail parties and were fine with multiple vehicles in the same area since the effects wound in a loop. These new rides are action, the scenes reset between takes. But I have a feeling with a little more money higher capacity ride systems could have been developed. Old Disney had no problem duplicating tracks if necessary. Of course, with the ticketbook system the capacities corresponded to actual value. I think I remember reading Tony Baxter acknowledge that the ticket system really motivated management to spend more on attractions, he may have even said he longed for it back. I don't think the low capacities were a creative or engineering issue. I think that Imagineering just wasn't given the funding to develop better solutions. That Beauty and the Beast ride at Tokyo Disneyland has crazy capacity, and I think that's because that's what their execs wanted.
Now here we are, and the hottest E Tickets are Rise of the Resistance (1,700/hr) and Radiator Springs Racers (1,500/hr).
I doubt I've changed anyone's mind. Some people think this is the best the company is financially and creatively capable of. Or that having more attractions to select from makes up for the lower capacity. Get your 10 attractions a day and be happy. Even though you might not even have a 50% shot of getting on the one you want most of all.
I should stop now. I enjoyed writing this probably more than anyone reading it. It was probably a bore and maybe confusing, because I'm not rereading it. But it puts things in perspective.
The flume and omnimover systems had never been imagined when New Orleans Square was first designed with two quant walk-thrus. Lucky for those guests the park overdelivered.