What’s wrong with Diana Krall?

Just wondering if anybody else saw Diana Krall on tour this past summer. I had been a very big fan and had previously seen her live years ago in San Francisco and Tampa/St. Pete. My recollection was that she was amazing in concert...she played flawlessly, she was engaging, and her ensemble was very tight. However, I took my wife to see her this past June in Memphis...man what a disappointment. First, they were 20 minutes late hitting the stage. Diana seemed like she was under some chemical influence...she mumbled her requisite bon mots to no one in particular, forgot lyrics to some songs (!), and basically took most of the night off, letting her bandmates do an extended jam session with lengthy solos on every song! Looking at customer reviews from her performances at other venues, this had apparently been going on for quite some time. Her whole set, including a halfhearted encore, was only about an hour. God, I hope she is ok and pulls herself together...what a terrible waste if she can’t.
Yes! I had the same experience. Twice. Once at her performance at the Beacon Theater in NYC a few years ago and recently at a “special “ performance at the Rainbow Room with Tony Bennett. At the Beacon she did everything as you described. At the Rainbow Room she was unapproachable, unlike Tony Bennett who posed for a selfie with me. I paid $1,000 for a VIP ticket and was treated like a poor relation. Something is wrong. In fact that’s how I found your post here. I googled “does Diana Krall hate her fans”.
'Few classical music lovers would think jazz bad taste , many are jazz fans themselves .Most I know think of rock as bad to horrible taste . They don't hate people who love rock, they pity them .' 

I think you're talking about an elderly generation that is dying off and did not grow up with rock. They are disappearing fast at this point. I haven't found it true of those that grew up with rock. I listen to mostly classical but also to jazz and rock.

There are interestingly artists who are more consistent than others in providing what the audiences came to hear. I've never heard of anyone complaining about Elton John or the Stones for example. I heard Joan Sutherland a number of times and she always delivered the goods. I saw Ella at Radio City which turned out to be not much before she had her feet amputated. I lucked out. I got a single 3rd row center to a sold out performance. The Music Hall didn't exist. I might as well have been seeing her in a nightclub. She was very wonderful. I felt privileged and it's a night I'll never forget. A dedicated performer even at the end of her career.
No such as 'good taste or bad taste', its just whether a given type on music fits one's particular palate.