this assumes that practice can bring your aim substantially, to the level of people with very good aim - this is not true.
most of your ability to aim is tied to your natural reflexes, which are genetics-based and cannot be changed - plus they tend to degrade overtime.
I have many e-sport players as friends (used to be one myself) and I always observe the same thing, their aim is excellent in most games they try, quickly overcoming people playing much longer with a lot more experience, and its due to the same fact every time, their hand passively moves faster and more precisely.
you can become better than you where when you started playing the game by remembering which weapons kick more etc, but so can everyone else, which is why you only improve compared to your early self, not compared to others.
why should people that won the genetic lottery be given an advantage over people who put the same time and effort into the game but don't have the 50ms reflex programmed in them?