Long story short: Tuco's assesment, that Larian just thinks its players too stupid is itself not the brightest argument, as other reasonings are way more likely.
Aside for the fact that I have no idea of why you suddenly decided to go completely ballistic with personal attacks on what was little more than passing side note (since the party size was definitely NOT the main point of my post, and if anything the way interacted with the OTHER restriction was the real issue)...
I somewhat appreciate your optimism (or your unwillingness to face being held in low consideration by devs, not sure) if nothing else because that's basically the exact reason Larian gave for other design choices they made: by Swen Vincke's own admission the very reason the game has "leveled enemies and monsters" that should NOT be a thing in D&D (and never were in the past D&D games) is because during their pre-EA focus tests it turned out that "People these days expect to see levels on enemies in games so we added them".
I can't overstate how much I'm not a fan of that choice either. This idea that "since it's a videogame it needs to be designed in a way that constantly reminds you it's a videogame" is genuinely terrible, as far as I'm concerned. But we are digressing and this is not what the thread is about.
P.S. And yeah, I'm not going to bother listing once again the dozen of reasons why I would prefer a larger party for reasons entirely unrelated to the difficulty setting when I already did it for moths and we have a thread specifically dedicated to it where I posted countless times.