Ronnie and Mick at Drury Lane didn't exactly display inabilities in terms of performing....ok, it wasn't a major long show, but still.
I think they're old enough to decide for themselves
I mean if it really turns out after a few shows that they aren't able to perform in any "decent" way, then they'll have to face the reality of not selling tickets in big numbers. I somehow cannot imagine that ( especially ) Mick isn't aware of this risk. I just cannot imagine Jagger putting himself in a situation where the Stones will be remembered as a band that should have stopped performing on stage. Some may claim this happened years ago, but look at the reviews from the Licks-tour. Even in this highly acclaimed - and critical forum
I simply hope that this next tour ( and perhaps the album ) will give us a few hints as to where they intend to go in the future. It could turn out to be a tour with much less dates. In smaller venues. As long as they can - they will. A "Las Vegas"-concept would of course a real nightmare, but can anyone really imagine that this will be the fate of the Stones ? I can't.
And btw, there're lots of artists out there much older than the Stones... and they still do great shows....
No need to worry. Too much. No nervous breakdowns. Happy Easter !!