Benjamin Franklin once proposed that the US Army should use longbows instead of muskets (or probably in addition to), because even in the late 18th Century the longbow in skilled hands was more effective than a musket. The problem is that little "in skilled hands" qualifier.
I used to shoot English style longbow with a group that did longbow demonstrations at renn faires. In California, all of the groups are named after saints, so naturally we were St. Sebastian's Guild.
Newcomers usually started with a 40 or 50lb bow. After a few years of shooting a couple of hours on two days a week, I was very comfortable with my 70lb bow, and was one of the few in the guild that could shoot the 110lb bow one of the guys had (there were many stringer than I, but technique is better than strength). It takes a lot of shooting over time to build up the muscles used for a longbow.
I also got to the point where I could hit our target (a 1.5m circle) fairly reliably from up to 50 yards or so. Beyond that, I had to arc too much for good accuracy. A heavier bow would have given me more accurate range.
But it took years to get that accuracy. At first I started out as most do, using my arrow point as a sight and learning how much above or below the target I had to line it up for a given yardage. Within a year I was one of the top 5 or so in our guild. Then I did a hunting style competition where we were shooting at foam animal targets at unmarked ranges and I was terrible because I didn't know the range. So I started what is known as "instinctive" shooting. You just look at the target and shoot, range be damned, aim point be damned. You are immediately lousy again. After another year, I was as accurate as I had been before, but I didn't need to know the range. It became like throwing a ball. In baseball, the shortstop doesn't get the ball, look at first base, estimate the range, and decide how high to throw. He just looks and throws, and it just goes to the right place. It just takes thousands and thousands of repetitions to train the mind and body.
After a couple of years, I could hit a 1.5m target at 50 yards, using a 75lb bow. I could probably have shot an 85-90lb bow a little more accurately, but still not much past 75 yards or so. The bows used in combat back in the middle ages were all over 100lbs, and accurate fire well over 100 yards was the norm. So after a couple of years, was still nowhere near their standard.
With a musket on the other hand, you just point it at the enemy and fire. They're so inaccurate that fine aiming is pointless. Beyond 50-70 yards the grouping was so bad that the finest marksman in the world wouldn't have been any better than a rank novice. All you have to do is get strong enough to hold the damn thing up for a few seconds, and any farm boy is probably already that strong. Oh, you also have to learn to load it, but that's not exactly rocket science.