I wonder how this will work, as all the sets & costumes etc. will go into storage. It doesn't mean the shows cannot be brought back.
When
Disneyland reopens, chances are small that it will have any shows the first few months. Even with the size of the Hyperion theater, if the park would reopen now, it would probably only be able to fill a 1/3 of the seats. Theaters all over the world are closed. Broadway, West End... it's the same everywhere. Here in the Netherlands only 2 big musical theater productions are back, with very limited audiences. The other shows are on hold till the world allows a lot of people in a small space again.
I can see it make sense now to announce the closure, to make sure people know what to expect when the park does reopen, and maybe 6 months from now we will get the announcement they will bring them back. Saying the show is closed instead of on hold, gives Disney probably the opportunity to let go of the actors instead of keeping them on the payroll.
Disneyland Paris tried to bring back 2 shows end of August, one show only played 2-3 weeks, the other one never reopened, as a cast member got Corona and they had to stop the rehearsals. They announced both are cancelled for now, but as they were popular I am positive we will see them again in the future.