What I am getting from all of this is that the question needs work.
A more useful question would be: which is more accurate on a match pistol- match-grade open sights or red dots?
OR- which is more accurate on an average pistol- Factory open sights or red dot sights?
I don't think the best open sights on a Glock G21 will get you as good of accuracy as you can get with a basic to moderate red dot on a higher end 1911-because there is intrinsic accuracy that comes from the pistol design- above/beyond the sight itself.
And then, it is useful to know what accuracy goals you have.
IF your goal is to regularly hit 4" circles at 10-15 yards in rapid presentations, then your sight needs would be different from bullseye slow fire at 25 yards.
I am entering the world of red dots, due to my failing focal ability under 4'. Front sights are blurry.
A red dot lets me see the point of aim and put it where I want it to go.
YET, I have noticed that I am able to get better group sizes with open iron sights than with red dots.
I have red dots on a Buckmark that has the scariest light target trigger I own. I don't let anyone except very skilled people shoot it, as there is almost no takeup, no overtravel and the trigger is about 2lbs.
I put a red dot on it, and I hit what I want, but- I feel like I can get smaller groups if I use the open FO front sight- it just takes me longer to line everything up.
There is so much science that goes into fine-tuning target sights that it has more adaptability to various needs than a 3mil or 2mil red dot. Even a 1 mil red dot at 50 yards feels HUGE.
Some of the dot options on my cheap buckmark red dot are just so large that I can only see using them if I were hunting a rabbit [or something larger] at 10 yards or so.
The basic dot is fine for fast action shooting, but I prefer iron sights for precision.
I am hoping I can last another 10-15 years before I HAVE to go red dot for handguns- and then I'll simply have to adapt to being ok with 5" groups instead of trying to achieve 1" groups of 8 in .45 at 10 yards.