Quite possibly the motive for wanting to go on later in the evening is that in major multi-performer concerts and recitals, it's generally assumed by most people that the major acts go on in the last half of the program, with THE major act coming at the end. It may be a "status thing" with some people.

'Course that could torpedo someone who's pretty good, but they wind up having to follow—well, let's put it this way:    I think most people consider me pretty good, but in a multi-performer concert, I'd rather not have to follow Gordon Bok.

Don Firth