Yep. That decision was made before Gettleman was ever hired.
I can understand not forcing Rivera to twist in the wind through the whole GM hire process, but I think it's abundantly clear at this point that Rivera just isn't the guy.
I am of the opposite train of thought. I don't get hiring a new GM and forcing the existing coaching staff on him. Seems like you're kind of undercutting your GM right off the bat.