Sadly, I don't know why, but I'm pretty sure it is because they can charge whatever they want and they will have a loooong list of takers... why discount it? I'm sure others can comment on other aspects
This is not a traditional hotel either. You won't be able to just book a night, or a week. It is an "experience" hotel, where you will only be allowed to stay for the predetermined length of the Experience (likely 2-3 days).
I'm not sure when the hotel is opening but the land isn't opening June 2019. All things point to late 2019. At Disneyland it is supposed to open sooner.
Thanks for the update. I hope we know at the 11 month window mark. I would like to get out to VGC a week before ST Land opens, counting on low crowds with only a week until the land opens. If it opens in the fall of 19, then a Jan. 2020 would be a great time to visit.