Mrdaputer,
I don't think it's as unusual as you suppose. I was a pretty decent competitive bull's-eye shot back in the '80s, but couldn't afford the time and cost of going to the big matches most of the time (though I earned a few pistol EIC points and was 9th in one national postal match in '89). However, despite posting high master scores on a good day, I wasn't consistently the best shot in our local league, and at least half a dozen of those guys could outshoot every production 1911 pistol I ever saw. I got wrapped up in learning to accurize and fit up 1911's precisely because of that. Short of dropping a large wad on a custom shop gun, getting anything capable of staying in the 10-ring at 50, much less the X-ring, did not come off the shelf.
The best target I kept from back then is the first one fired after fitting up a Goldcup I had that shot 4.5" at 25-yards out of the box. This was off bags using an Aimpoint sight on a grip-panel mount with handloaded 200-grain JSWC's:
The way I could tell I was having a good 2700 match back then was that my .22 and .45 scores would be about the same and occasionally the .45 scores would best my .22 scores. Not counting the less experienced competitors who still had a lot of flinch fliers, most shooters I knew back then had better .22 scores than .45 scores because most had .22's that were more accurate than their .45's. But I didn't. So the precision of the weapon made a definite difference on paper.
Target shooting probably is the best test of the accurate gun's influence because even a poor shot will usually post a higher score with a good gun. I have several times loaned my match-accurized Garand and match ammo to beginning shooters who had been posting scores in the upper 50's to 60 percent range with the loose club loaner guns and ball ammunition at our 100-yard reduced range matches. All gained around 10 points with the good rifle and ammo. On two occassions, personal bests were posted that way. Mind you, still low scores, as the seasoned competitors went, but pretty exciting for the new shooters and it encouraged them.
That sort of marginal score improvement happens for statistical reasons. Even poor shots will usually throw a number of almost-shots during the course of a match, and with a good gun, an improvement of just a couple of percent in their group size will cause some near-scratches to "make". The bottom line is, most people can actually benefit their scores by having an accurate gun. Whether or not it outshoots you is not really the only consideration. It is whether or not poor shooting can be made even a little better with a more precise weapon. It can on scoring rings. On steel plates, it is harder to tell, so some of this is an activity-specific benefit. Nonetheless, if you have a gun of unknown precision, but know someone with a tuned custom gun, see if they will let you try it and see if you do better with it. Then you can decide whether you need one or not.