To be honest, having older gear that you are intimately used to is better for the 'entertainer' than something you are struggling to learn, constantly. You only have to look at Donny's posts, as he struggles to get to grips with every new arranger he buys. That has GOT to make for a few uncomfortable gigs... plus a LOT of homework, as you try to make the new arranger simply do what the old one already did!
I've backed a LOT of artists in my day, and one thing that seemed a constant (and these were TV and stage and radio stars) is that NONE of them ever had anything approaching the state of the art for its day. Old keyboards, old guitars, old amps, old effects... I have a feeling these guys find out what WORKS, and just stick to it!
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An arranger is just a tool. What matters is what you build with it..!