Can anyone explain this to me please?

[LB Freakazoid]

Oh geez, gotta defend Stevie here - but in the end.. Not.

Years ago, she would say in interviews as to why she would change - shawls, etc. between songs - and i'm paraphrasing - she wanted to give a visual to the song... No one just wanted to see someone standing up there singing a song...
This was waaaay before Madonna, Janet Jackson, etc... Though, they took that to a whole new level, hence, now most concerts-shows are indeed, traveling theatrical shows.... So, good for her...
For the rock'n'roll show... Well, depends who ya see... Right now, Queen with Adam Lambert are doing the rounds.... Great concert and show - same costume changes, same banter - however, fantastic show.
I think that unless you're seeing a jam band and/or total r'n'r i.e. dave mattews band, Leogun, etc., you're going to get huge name bands with the KINDA the same thing show.
Those huge shows have so many components with lighting cues, etc... That it has to be formatted. I've worked them... Every 'moment' is cued.
I've done 40 city tours with corporate executives - same speech in every town... They got excited with a one sentence ad lib, "it mixed it up a bit".
So if they think THAT was huge, can you imagine someone who has sung a song a gazillion times feels when there is just a little banter?

This is what they love --- however, it is a job. Remember that.