I haven't tested many different pistols at 50-100 yards. My best centerfire autos (75B plus CGW bushing, 97B"E", and P-09) I can demonstrate 3-6 moa every time I take them out. The three factory Sig P-226s were more like Boris says, I typically could shoot 8-10 moa and the one Sig with a fitted Bar-Sto barrel that I fitted is closer to the CZ, but not quite there.
To me, pistol accuracy guarantees are a marketing strategy based somewhat on statistics but also on human nature. People that expect good results from their guaranteed accuracy pistol may actually shoot them better than they would one for which they had lower expectations. I'm guilty of that myself. I fully expected (and was right to) my 97B"E" to be a 3 moa pistol out of the box (with no guarantee), and it was. I expected some improvement with the 10x bushing in the 75B slide and I got it.
I'm no gunsmith. But there is more to repeatability in a pistol than just the mechanical tolerances. There is the lock up timing. This is where the CZs plus the Atlanta Arms 115gr ammo seem to work better than the Sig, for example. The Sig with the fitted barrel is tight, but it isn't quite as repeatable as the CZs. I suppose the barrel starts dropping down sooner than the CZ, "unlocks" sooner? I don't know.
I'm to the point where I'm not sure I could shoot a 2 moa capable pistol to less than 6 moa on average. My 75B with CGW bushing may BE a 2 moa pistol and I just can't demonstrate it. On the other hand, I can shoot a sloppy pistol to smaller groups than many people. I don't have any trouble identifying a 10-20 moa pistol and declaring it to be too sloppy for me. There aren't many of those out there, in my opinion, fortunately. My example is my own 75B 9mm slide before the bushing swap.
When I first started shooting pistols, I thought all pistols were sloppy and needed adjustable sights because they wouldn't hit in the same spot from day to day. Eventually I learned that it was me, not the pistols. After I learned to shoot, all pistols became more accurate and I no longer needed to adjust the sights every day. Same with shooting at 50 and 100 yards from a rest. There is a lot of technique that one must become good at before one can demonstrate how good a particular gun is. I'm not there yet, but I'm further along the curve than most people. On a normal day, I can certainly identify a poor pistol/ammo combination.
Truly sloppy guns are easy to identify. No one can shoot them well. Truly good guns are harder to identify, as good shooters can always shoot them well, but less experienced shooters may not. The less experienced shooters are quick to blame the pistol. The more experienced shooters know better.