Garth Brooks is back out of retirement and in Vegas, does he still have it?  

Sure he's still got it. I grew up listening to George Strait. I even got to go to one of his concerts, it was the #7 Tour, that was a long time ago though. I'm sure he will bring in a crowd that loves country music. It won't be like a typical Vegas show because he is all class and not just some show to go see.

It won't-be/probably-wasn't as 'kickin`' as it was back when he was in his 30's and 40's, but the marketing-Major's training is as eternal as the mountains

Besides, 'out-of-retirement' to musicians just means 'back on tour or -on a concert-schedule' ... not much difference between 'retirement' and 'working musician-hood'; it's explained in Bachmann-Turner Overdrive's song "Working for a Living"---'If you e-ver get an-noyed, Look at me; I'm self-em-ployed. I love to work at no-thing all day!'