People think top singers are overpaid, but opera houses have a top fee, which is a good thing. Of course concerts are different- everyone wants to make as much money as possible.
If you have a recital to do, you have to memorize the songs. I never use music when I do recitals. It produces an instant barrier, both for yourself and the audience.
I think every singer should be able to jump in for a singer who has been sick, for instance, and learn an opera in two days. I know people who can do it.
Good acting is about being as natural and calm as possible. These days producers have such definite ideas that you have to be prepared to do whatever they ask.