Not having the time for practice, and going racing instead is fair enough. But in my opinion and experience you also need to dedicate some time for pure training on the boat aside from the disturbances of racing. There are so many different things to work on, and while racing you might e.g. get to do 3 spi sets and douses, that is not nearly enough to optimize how to do it. Even if you concentrate on doing the tacks in a special way and working on those, you _will_ be distracted by the fact that you are racing.
It's the same thing with every sport I have done. You need to practice the basics if you want to be really good, and sailing is a very technical/composite sport where you need to be on top of both the physical side of it (movements, timing, balance, endurance, strength, agility etc.) and the mental side.

Now, when I was boxing, I did not start out in the ring. But worked on the basic movements, guards, blocks, taps and punches. When I mastered this, I could move on and do some controlled sparring before I was able to go into a match. Sailing is not directly comparable to boxing, but it's a good analogy as you will get murdered on the racecourse if you go out there without practice.
You will of course get better/faster just by racing. But my point was, and is, that you will be doing it the really hard way and you will probably never reach your true potential.