You make a good point - accuracy is relative to the gun and what it was designed to do.
A prairie dog rifle requires less than 1MOA accuracy out to buy500m, and it would be even better .5MOA.
A combat rifle only needs 2MOA accuracy and 6MOA is considered the threshold for a necessary replacement.
Minute of prairie dog and minute of man are about the extremes of accuracy. That is why the smarter buyer will ignore Brand of a rifle and focus on features. If you need a more accurate rifle then you specify the needed features to get to that goal.
The barrel is most important, then the ammunition. Barrel length may not be important - depends on the cartridge or application. Velocity can even be counterproductive. You can push a bullet too fast and create more group dispersion. Most handloaders discover that downloading the recipe slightly from maximum pressure almost always results in higher accuracy.
When shooters focus on cartridge or bullet size, barrel length, and accuracy, what they are more likely doing is emphasizing the social aspects - I got one and you don't, therefore, I am better than you. Forums are full of that immaturity and it will never go away because young men jockeying for social respects all too often key on things that their less well informed group members find impressive. So, they adopt them to maintain their rank - not because the item itself is all that.
No question the .50BMG is top of the heap in a one man crewed weapon, what's popular right now? .300Blackout, which has been around since the 1980's as a wildcat to get AR15's into 3Gun in the days when real men didn't use jammomatic poodleshooters. Well, we sure got over that, and we will get over the next cartridge of the month club craze, or long barrel fad for a short barrel cartridge, or whatever.
It doesn't change the real basics of ballistics and the adults will use them appropriately, regardless of the latest fad.
