This is true to a certain extent. It depends a lot on what OTHER people are playing too though.
I'll use rock paper scissors as an example. The arena is made up of rocks, papers, and scissors. You are consistently playing rock, so you may think that the amount or scissors will decrease, while the amount of rocks stay the same. However, there are also a lot of people playing scissors and paper as well, so while you are beating the scissors and sometimes the rock, there is another person always beating the paper and sometimes the scissors.
Now the caveat with this is that if rock is faster, then even if scissors is winning against paper consistently, you are encountering more than what the scissors can keep up with. Then on the other hand, you may be able to develop a rock that is able to beat paper, and not scissors. ect ect.