This experiement's point is clear and identified in the article. This is pitched as an alternative to going to a cinema and it is priced lower than the cost of bringing a family there. If it works, and it may do quite well, indeed, it will be a massive blow to cinemas but we need to keep in mind that these are not normal times and people currently have a strong incentive to stay home.
That's the thing. These are not normal times so "Mulan on Streaming" is not competing with "Mulan in the cinema" or any other movie in the cinema. You either watch it or you don't. This movie is targeted at tweens/teens and the FOMO effect will be big. So if you have a tween in the house that wants to see the movie, you will pay those 30$. Not to mention the tweens who will be more than willing to shell out their own…
The question is whether people are willing to pay the same or a bit less (of course I'm thinking in terms of US/Western Europe prices) to watch new movies at home rather than in cinemas.
At the moment perhaps, but in general I am not sure because I think people go to cinemas not only for the movie but for the whole experience.
But I'm sure that the cunning people of Disney have factored the fact that these are not normal times in the pricing of this specific movie at this specific moment in time, and they'll see how it goes.