Maxwell, watch it again. The glint in the eye, the half-smile: maybe you are missing the wind-up you know, the irony?
I'd say, having watched 19 concert performances (some acoustic) over the last 20 years, Steve certainly rehearses...buy a ticket for the next show near you and discover a consummate professional at work - rehearsed to the finest detail, in this fan's humble opinion - how else could Steve get away with all that improvisation? The band are constantly having tofollow changes in the set-list it seems.
He doesn't owe anything to his fans that we don't get, in spades.