Since I have NO idea what I'm talking about, I think I'll join in too.
I would say that in history the general populace of THAT day were better shots than the general populace of THIS day for several reasons. There was a larger portion of the population living in rural area than in urban areas. Rural people shot guns more often than city folks. However, city folks of history shot guns much more, as a percentage than city folks do now. (gangster excluded) I didn't say that shooters of that day were better than shooter of TODAY, I just can't see how that's possible.
Therefore, if someone is shooting more often and FOR A REASON (trying to kill their food), then it stands to reason that they would be a better shot than those who never do shoot at all or just shoot for fun one or twice a year, no matter how GOOD the gun or ammo is.
However, the OP question had NOTHING to do with rural vs. urban, nor modern day, but that's not going to stop me-no sir.
Today's shooters would be considered very accurate shooters if put in a historical perspective because we have so much more money and so much more time to practice-as has been stated several times in this thread.
Chronologically, as close away as my father and his brothers having to provide meat for the table in the late days of the Depression era, HAD to be good shots. This was NOT that long ago, or so I keep telling myself. So, having to learn how to aim and shoot was part of their everyday life. They were-as I was, born in the rural south. It was a necessity to shoot well for them.
For me, it was just fun. I never HAD to shoot anything to keep meat on the table, my shooting was all for fun. I learned to shot BB guns with my cousins as a young child. We walked "patrol" on dirt roads and (sadly now) shot and killed just about anything that crawled or flew day after day. So, we got pretty good at it. We hunted as kids in a large group of relatives. You shot good because everybody did.
Something else to consider-People can also SEE a whole lot better now than they used to, don't neglect that either in your theories. My Grandfather (b.1899) was considered a very good shot because he could see really well, my Dad (b. 1929)was a bad shot because he had astigmatism. It could come down to simply the fact that people of history didn't have glasses or at least glasses that were much good.
Now back to people who know what they are taking about.
OJW