How do I tell these performers, many of who I have known on a first name basis for 30 plus years that they no longer have what it takes to play my venue, without hurting their feelings?

You DON'T tell them that, unless they ask you exactly WHY you are not booking them. Tell them something else that is also true, but not hurtful.

"I don't have an opening available."

"We're going in a different direction."

"I sure wish I could book my personal taste, but it's pretty complicated."

"Our venue is not the best fit for you right now."

"I handle all the arrangements, but choice of artists is something done by committee." (there you get your second opinion)

~Susan