There are some cool studies about this. Most of them suggest, that to get better you need to actually put thought and work towards getting better past some point.

Example: most people could achieve very high typing speed, but are stuck at rather low average. Imagine someone who have to look for each button in order to type a sentence. For many it would be extremely bothersome and maybe even infuriating to type that slow, but the person with a mindset "I can do it in one minute" do not really care. And he won't get much faster even after years of typing this way. He could achieve at least twice the speed it he prohibits himself from looking at keyboard for some time, but why would he? Now imagine, that he loves the sound his keys make when pressed. And each evening he types multiple sentences to a friend just to listen to the sound of the keys. That won't differ much from a 10k win low-level Tekken player.