It's because the numbers do not work with the capacity Disney has, the demand Disney has, and the ride capacity Disney allocates to the line skip. If all those other parks had the same ratios Disney has they would perform just as poorly. I guarantee if Cedar Point only had 4 roller coasters (lets say the ones on Fast Lane Plus) in the park and not 16, their line skip would blow up things just as bad as anything happening at WDW right now. For Fast Lane Plus, which includes the best coasters it even specifically says "A very limited number of passes are available each day." Unlike Disney which tried to make 80% of daily ride capacity use the skip option.
The other parks *know* when you offer too many people the option to skip, things break. If Cedar Point sold 80% of those rides capacity via Fast Lane Plus like Disney and FP+, it would break. I don't even think Disney can offer Universal's Express pass because demand is still >>> available capacity because people have been trained that you have to skip or your day will be ruined. Disney is the one with the most complaints because they're the ones with system that isn't designed for their crowd makeup and ride expectations. But like I said to you earlier, people will only believe it when things are so bad that every seat on the top rides are sold via line skip and it still sells out in minutes and people can't claim their seat in musical chairs ahead of other people.