I believe instinctive aiming can work very well out to fairly long ranges. By long I mean out to near the archer's point blank/ point on range. Near point blank range the tip of the arrow comes so nearly into the line of sight it is impractical and unwise to try to ignore it.
Some archers have short point on ranges, down to 30 yards and less. But a good many of us have long ones: 50, 60 and longer with a long draw and efficient tackle. With my longbows and 500 grain wooden arrows my range is 55 to 65 yards. With a recurve and 400 grain arrows it is over 70 yards, and I have heard of 90 yards for fellows who use carbon shafts. Under these circumstances there is little choice about shooting the short and middle ranges instinctively. Gaps may exceed 5 feet at 40 yards or so. The point of the arrow may cover a point 12 or so yards in front of the target. Your conscious mind cannot deal with that very effectively. But the subconcious can, with sufficient good practice.
Here in Northern California we often shoot open 3D and field archery to the full 80 yards of the field course. Half the targets may be 45 yards and more. Most folks gap shoot or use another system for at least the longer half, but not all do. And there are some who can shoot these events really well mostly by the instinctive method. There is one fellow I have shot with at two events this year. Hereabouts the top possible score is 924 and the compound pros go over 900 at a 42 target 2 arrow event with an 11 point spot. 500 is a good traditional tackle score and some top hands go over 600 even with a longbow and woodies and occasionally a point of aim shooter goes over 700 with a recurve.
The fellow I am thinking of shoots take down hunting recurves of around 50 pounds and aluminum hunting weight arrows. He shoots with the split finger hold, cants the bow and says he shoots purely instinctively except at 70 to 80 yards where his arrow tip is nearly on target. He doesn't even want to think or hear about gaps, for fear he will start to notice them in his sight picture.
In the two events I shot with him he went over 700 points and in the last he was over 750. During the second half of it he shot over 400. It was amazing to see and I was so jealous I could have spit. But upon reflection I am pleased and inspired to know that much more is possible than I have so far achieved.