When I first started competing, I often looked a little sideways at all of the fancy guns people brought and the complicated-looking gear shooters strapped on to their guns and themselves. Why would anyone need all of that "stuff"? Did better toys make for better shooters?
Not directly. You can't buy your way to being an expert marksman because your physical and mental technique underlies your success as a shooter, no matter what gun is in your hands. However, having the right gear can help in a couple of ways.
First, it can be more forgiving of mistakes. When I started shooting IDPA, I used my Sig P226 DAK with a 6.5/8 pound trigger (and I do use the short reset, so I spend a lot of time with that 8lb trigger). The results weren't pretty. Not only was the gun too big for my hands, making certain manipulations suffer, the long and heavy trigger amplified the many beginner mistakes I was making under the stress of the timer and the movement. After watching my frustration mount because I was having trouble even hitting targets, I was switched to a Smith & Wesson M&P 9L with an Apex Hard Sear. My improvement was almost instant. Not only did the dreaded Failure to Neutralize disappear almost overnight from my score sheets, my times dropped at the same time. I didn't suddenly become a better shooter, but my new gun was simply nicer about problems like my tendency to drop shots under stress with a big gun and heavy trigger. And not having to fight that particular battle helped give me enough positive feedback to keep going back for more matches.
The right gear can also help set you up for more successes even when you aren't battling your own problems. You can be nailing your technique, but picking up that drop-and-offset holster and those fancy mag pouches could shave a precious tenths of seconds off your draw and reload because the draw stroke requires a few less contortions and you aren't inadvertently grabbing an extra magazine. Shelling out for the PMAGs might save you from having to clear an extra malfunction or two when you're using a rifle magazine as a monopod for a long shot. Buying a quality optic and pairing it with a solid mount will help prevent your groups from suffering because you can't clearly see your target or because your zero is wandering. You can do everything right but if your gear fails you, you'll still be at square one. And at the end of the day, not having to fight your gear can make a day on the range far more enjoyable and allow you to concentrate on really making sure you're doing your part instead of getting your gear to work for you.
Oh, and my Sig? I installed the E2 grip kit and expect to be bringing it back out for matches soon. Don't fear the gear that wasn't right for you in an earlier life either.