That is a pretty lofty goal. The military standard for a prone supported group is roughly 1 inch at 25 yards, or about 4 MOA-ish if you bother to confirm zero at 100, 200, or 300 yards (depending on what sights/optics you are using). For offhand, I don't think doubling that (or even a bit more) would be ridiculous. Something around 8-10 MOA with iron sights or even a red dot seems like a good starting goal for off hand. That's still going to hit a man sized target at 200 yards most of the time.
I guess taken out of context my response was not totally clear. I agree with you. See post #8 above.
I actually think the OP posed a great question. I didn’t realize it a few years ago when I got my first AR but I had a lot of the same questions myself.