I usually attend MK concerts together with people that doesn't read forums, listen to bootlegs etc. And even if these people hear many of the same jokes or anecdotes tour after tour, they don't remember that he said almost the same thing two years ago. What they notice is the new jokes, the variations etc.
What we/you are talking about here is very normal, I think. Even Bruce Springsteen (whom I've been to more concerts with than MK) repeats himself show after show, tour after tour, (and has been critisized for it by his music friends, Southside Johnny, for instance), though he has loosend up a bit lately.
And the band, I'm a 100 % sure they don't bother at all! It's all a part of the show. When you're an actor, you do the same show after show, and so do the fellow actors. If you play classical music you do the same show after show. And it's more or less the same when it comes to rock music. When I'm doing speeches and courses and such together with other people, it doesn't bother me at all that the other ones make the same openings or tell the same jokes every time. It's all a part of the "show". (I say different things every time, and the drawback is that my speaches vary more in quality than many other's, but my best are quite good
.)
So I know what you are saying, and it's an interesting discussion, but I don't think it's that negative.