The other side of that coin is the viewing comfort the larger exit pupil offers, regardless of the ability of someone's pupil to dilate sufficiently to take full advantage of it in the sense you imply.
10x is my preferred magnification, my 10x32 EL's are my default daily binocular, but increasingly I'm opting for bigger and heavier binoculars in 10x format, for the more relaxed view and the luxury of being able to move my eyes around within the parameters of the exit pupil. For the past several days I've carried my 10x50 EL's and enjoyed the wonderfully relaxed, immersive and uncorrupted view. For me, 10x50 is probably the format I enjoy most, due to the combination of magnification and size of exit pupil.
I love my 12x50 Ultravid, but have a suspicion I might love a 10x50 Ultravid even more, if it fits me.
I can relate. Apart from my-then Vortex 6,5x32 I've mostly used binoculars with a ~4 mm exit pupil, even 3,2 has worked well. But here's the thing. My EDG 7x42 proved extremely sensitive with eye placement and I had to add spacers below the eyecups to get the exact eye relief, and also a Vortex Bino-Loc to ensure the IPD stays put. Then it's a completely different beast. My new MHG 8x42 has that extremely relaxed view you suggest.
It's just that great viewing comfort isn't linearly proportional to the exit pupil size. True, a ~4 mm EP statistically demands greater care with eye placement so I see where you're coming from. Personally, I prefer more magnification if the binocular is that large.
Twilight number is a thing, really. In dusk or darkness, the sharpness does very little. But the area of an object viewed through a 12x is 44 percent bigger than with a 10x, and if your own pupil can't dilate enough, then magnification is all you have to go with.
I was torn between 8x42 and 10x42 when I chose the MHG, but I'm confident that the 8x was the right decision. I have no FOMO and when I've tried the 2,5x booster I really can't see more than with both eyes at 8x.
We have much flatlands in my area with some really long distance viewing and more magnification makes more difference at long distance than short or medium distance, because you must move a lot to get sufficiently close to compensate for the smaller magnification.
Edit: Clarification: I believe I can do a lot, maybe everything with an 8x and don't feel the need for more power at least at moderate distance. With much greater distance, nothing beats magnification.
In my experience, the scope magnification can be no less than 2,5x the binocular magnification, preferably more than 3x.
With my Meostar HD 12x50 I have a decent overlap when going to 30x in the scope.
With an 7x or 8x binocular I find 27x ideal with my ED50A, and even 30x with the bigger scope is OK.
//L