I think the price point was absolutely the biggest problem. I don't know how Disney thought that kind of experience at that cost would ever have a large enough audience to be sustainable.
While it didn't look like an experience I'd personally enjoy -- despite being a massive Star Wars fan at one point in my life, although not so much now -- I think there are a lot of people who would have gone at a lower price point. The asking price was absurd.
It's possible that price point was the only way Disney could turn a reasonable profit (especially since they didn't even try to offer discounts before shutting it down), but in that case, there was a significant design failure somewhere along the line.
The one smart thing is they under built it with only 100 rooms. I think they really failed at marketing the experience as a premium offering to those who might even consider spending that amount, particularly by not really involving the OT - fans of which are most likely to have that kind of money to burn, given the demo.
As others have said, if Universal offered a 2-night Hogwarts experience for $6K that involved being sorted, a big banquet dinner, simulated quidditch, lessons by Professor Sprout and others, along with and some other cool experiences, it would be sold out for the next two years.