Any predictions on when these will reopen? Vaccine won't be until 2021 (earliest is late winter) and then it will be supply and demand for the entire world, so anticipate world-wide immunity not until end of 2021
So I am HARDLY an expert. I understand enough biology to get the science of what is happening since that's my degree, but I am not a front line worker nor am I in any way affiliated with Disney or the entertainment industry. In other words, take this as MY PERSONAL OPINION with no basis in fact.
That said, I will repeat what I said in another thread. Even with the success we are having, Vaccines are a tricky business. The fact that we have had no major roadblocks and are seeing an immuno-response is AMAZING, but almost always a shoe will drop and I expect we will have one at some point. The advantage we have in this game vs 10 years ago when we were fighting HIV for example is that we have so many possible candidates. But developing a vaccine is still only step 1. There is distribution. There is social acceptance (which is a bigger problem than you might think). And although they are promising 100 million doses available as soon as it's approved, those 100 million might not go that far if it has to be re-applied every 3 months.
HOWEVER, there is another avenue which makes things less dire. That is an effective treatment. We have had very promising results in that area. Unlike a vaccine, treatment has a lot less roadblocks. Mass distribution is less of a problem since not everyone needs it and it's only used where needed so requires far less. Also, most of the treatments we are finding effective are widely available easy to get medication.
Put these together, and my prediction is that late in 2020 we will have effective therapies for people with COVID using mostly OTC medication. It will become closer to the flu - dangerous for a percentage of the population, but for most of the population it means bedrest and meds - not fun, but not deadly. People will become more bold because it's no longer life-threatening to most. The government will push toward being "normal". Still, it will be widely rampant because it's more communicable - it will remain a news item, a source of fear and largely politicized. A vaccine will come along after that - but it will not be until mid-late 2021 before things return to "normal".
I realize this was not your question. Water parks WILL probably re-open before this normal. If I had to guess, I suspect Disney will wait out this season, and re-open one of the water parks early 2021 trusting that people will be emboldened by therapeutic treatments and aim to have them both open by next spring. The question as to what the water park experience will be - that I have little guess on (possibly using swimming water masks, or allowing their removal in some areas - I just don't know).