Wait, how do you assess if a player is ready or not if not for how they perform at the major league level?
How do you assess that a player was not rushed when he's putting up historically bad numbers to start off a career?
Now I agree with you that Elias has a better feel for when he should go back down or not, but I don't think Holliday has proven anybody wrong who thinks he was rushed. His performance so far if anything has proven them right.
Can he right the ship and prove them wrong, sure, but so far, anyone who says he was absolutely ready have been proven wrong. He's not been just unlucky, he's been terrible at every measurable attribute we have for hitting.
There is also a misnomer that players can not learn anything else at a previous level. That's just wrong. Having statcast data now shows there is major league caliber stuff in AAA, it's just often not consistent.
Plus, the ability to just relax a little work on the things the major league coaches have him working on in a less stressful environment can also be a plus. He has 147 AA PAs under his belt that he put up a respectable .899 OPS, but he's also a kid who had a 105 PA stretch last year in High-A ball where he put up a .183/.362/.232/.594 slash line where he had two extra base hits and basically only got on base by walking against bad command High-A ball pitchers.
Holliday has a tremendous amount of talent, and he's going to be fine in the long run, but I disagree that sending him back to AAA will do him no good. Will having him set more futility records to start a major league career be helpful? If we get swept in a series and he goes 0-for does that mean he's now hurting the team?
I'm ok with leaving it up to Elias/Hyde to make that decision, but I would have zero issues if they sent him back to reset for bit.