No. I'm not making a prediction,
You have to though. You're banking everything on your belief it's read for D&D. So, then, you have to predict people would answer that way, or lie.
So take a position. You either believe it to be true, in which case you're predicting people would answer that way, or you doubt the veracity of your argument. Which is it?
I'm stating that the default effect is real and significant, even though D&D says right up there in front that you can change anything you want
How is this not a prediction of how people would answer the poll? It's real and significant, but you won't risk answering my question about how people would answer the poll? Either you think it's real and significant, or you do not. Let's find out, right? I want to see you tell people they're all wrong about their games, or lying, when they answer they would just change it. I want to see you tell people how your theory, which was not applied to D&D in the study, holds true for their actual games, despite them telling you it's never held true for their games, in any version of D&D.
If I was to predict what the fallout of assuming a default in 5e might be, I would predict that it would be something like the fallout from presuming a default in 4e.
No no...ALL versions of D&D. They ALL did this. They all had fluff, and they all had an explanation in the DMG that you can change the fluff for your games. Not just 4e, which is entrenched with a host of other issues that caused a rift in the D&D community, ALL D&D. Your argument would have resulted in almost nobody changing monsters over the years. It presumes the forces against house ruling are tremendous - in the 90% or so. Which is why I am saying you already know your theory is false as you have tons of evidence this game doesn't play out that way.
You have some people that love it, you have some people that adjust certain elements of it, and you have some people that just say "Um...no" and go play Pathfinder (or whatever).
But Pathfinder also does this. If you're theory were true, they'd be just as upset about it with Pathfinder. But no wait - they wouldn't ever be upset. They would just almost always go along with the fluff no matter what it was. That's your theory right, that people just use the default no matter what. So, why are you predicting people would get upset and choose a different game? That seems entirely inconsistent with your theory.
This regardless of a big Rule Zero printed right up front. 3e had that, and a lot of folks still thought you should play the grapple rules as they were written.
And a lot changed it, but more importantly we're talking about stuff that is super-easy to change - fluff about a monster. No math necessary, no balancing with other things in the game needed, no connection to a series of other rules about ability scores and circumstance bonuses and all that. Just monster fluff. You're honestly claiming people didn't change that in their games at-will if they didn't like that, despite all the evidence you have people have routinely done that.
4e had that, and a lot of folks still decided that they'd go with demon succubi in PF rather than change a keyword in 4e thankyouverymuch.
Ah ha! So we know, for sure, that people DON'T DEFAULT TO WHAT'S IN THE BOOK. If your theory were true, they would have just accepted the 4e version. But your theory proved false - they went with an entirely different description than the one in the book, from a different game even! So why are you arguing this theory is true for D&D when you already know it's false?
This panicked false duality ("If we don't have WotC telling us what monsters are like, we'll have NO MONSTERS!") keeps popping up, and it keeps being woefully misinformed. The alternative to a default isn't nothing. It's a field of options!
If you have infinite space, sure. But you don't. Realistically you have room for one developed description, or else you have several undeveloped ones. You cannot do both, in the space provided. So they're choosing one developed description, like every other version of D&D before this one. And like all those other versions, if people don't like it, they will just use their own or one from a different version of the game.