Those original guidelines were essentially not obtainable for months, maybe even a year. It's not just the limited capcity in the park. It's the tier level required before opening at all. The Yellow tier, which was the proposed tier for parks to reopen, says that there can't be more than 1 new infection in 100,000 a day... oh, and it'd have to stay that way or less for 3 weeks, or else forget it. If 2 people in 100,000 get infected in the same day, back to Orange tier for you, which means another 3 more weeks of waiting to open. You can probably see why this is difficult to achieve in current times.
Let's put it this way... if these standards had been the guidelines for Florida, none of those parks would've ever opened in the first place. They'd still be sitting with empty theme parks, just like we still are.
I consider myself pretty covid-cautious (I still wouldn't feel safe flying, and am never without a mask in public), but even I feel that an Orange tier, combined with lowered capacity and other park precautions (already modeled in Florida), ought to be enough. And Orange tier is going to be hard enough... no county in Southern California has it yet, although as I understand it, the OC may be getting somewhat close to that. LA County is still in Purple (the highest tier), so it's going to be a while for Universal and SFMM to be back open, even if the guidelines do go down to Orange.
Oh, and Brian G., thanks for splitting the thread! As a west coast guy, I must admit I'm more focused on happenings out here, and it was hard to get west coast news with all that is happening in Florida.