because they wanted to
Plague closed the theaters. it is a disease.
Bubonic Plague
There was a plague. All of the theaters were closed for public health reasons.
The London theaters closed in 1593 because of an outbreak of plague.
There was a particularly nasty outbreak of the plague in London at that time.
London Palladium and Victoria Palace
The Leaders in london did not approve of theaters
The schedule of musicals at some of the London's popular theaters can be found at various websites like London Theater Guide and Official London Theater.
the mayor of London.
this question is usless
One can see musicals in London from a local high school theater production. Alternatively, local private and public theaters often host musicals as well.