Apropos of the curse, an explanation that I heard from a reasonably famous Scottish stage actor:

Macbeth is Shakespeare’s most popular play, cause it’s got sex and blood and poetry all over, a really tight plot, and it’s not too long. It is pretty well guaranteed to fill a theatre. Also, every actor knows the script so you can find a cast in no time.

So if your current play is not selling a lot of tickets and is about to be cancelled, the theatre is going to put on Macbeth right after you to try to make its money back quickly. That’s why thespians hate to hear the name ‘Macbeth’ — because if there’s talk of that play going about, you could be out of a job next week.