Yeah, and they called the later boarding groups at an accelerated rate. Sounds like they are loading up the queue, hoping to clear it by 10, and getting to work on making sure today's issues don't repeat.
While I understand the sentiments of some of those who are dissatisfied, as an engineer who works on complex systems, I see nothing out of the ordinary here. Disney could have played it safe and given us an attraction that would have high reliability and fewer moving parts...and a lesser experience. With Galaxy's edge Disney has declared that playing it safe is not their mission. They are trying to do the impossible. And, as it happens, doing the impossible means pushing boundaries and taking risks and accepting some down-time. The technical aspects will improve over time. 3 days here is not enough to determine anything resembling a trend. And even with 6 weeks of data in Florida, we're just starting to see what might be an improvement trend.
Early adopters always pay the price for being on the bleeding edge of innovation. And that's what the folks that are riding this now, at release, are. They are the early adopters. They exchange reliability for the opportunity to be the first users. Software these days is never released bug free. The first commercial users are essentially the Beta Testers. You can think of the cast member preview as the alpha/smoke test, and the first year or so of regular riders as Beta. Bugs will be reported and fixed. Some bug fixes create or expose additional problems. Shortcomings in some of the mechanical systems will be discovered and redesigned to be more robust. And over the next year you'll see the up-time improve until it levels off at something close to the expected capacity.
Now, the people-angle issues we are seeing I expect will correct a lot sooner. If the ride is down for an hour and you are held captive in the queue under threat of losing your BG, that's a problem I expect will be solved quickly. So please bring that up to Guest Services and name names, not to punish, but to help those CMs get the training they need to deliver a Disney experience.
Honestly, the people who built the land love it far too much to allow it to languish or be mediocre in any way. If all this is too much for you, skip it and wait a year or so. I would be willing to wager that reliability and throughput will improve.