My only opinion would be what you say in response. I would recommend something no pressure is all.
"I'm really sorry your plans fell thru, I think you'd have had a really fun time in vegas" (noted* not fun with you, theres no you/me or we right now)
Of course its your wife, and you know her better than anyone here to say the least. I don't think you stating your dissatisfaction with her is gonna give you the results you would want either way is all imo. Or even that she might feel she owes you an explanation, might come off as controlling, or passive aggressive.
