You have visibly a fundamental misunderstanding about mining blocks.
If you have hash power that is so that, with a given difficulty, on average, you find a good block, say, every hour, which means that you have about 1/6 of the total hash power *when the difficulty was determined*, then it doesn't matter whether others are mining or not, you will win, on average, one block every hour - minus those few seconds that you were mining on the wrong block each time.
your not getting it at all!!
ok try this..
imagine the olympics 100m
5 guys.. they all run
average is 10 seconds to get to the other end, and only 1 guy wins
This is simply wrong, because the mining process is not a cumulative work towards a solution. Every hash is a random trial, independent of other trials. It is not because you have been hashing for 20 minutes on a block, that your probability of finding a solution in the next second is higher than if you just started hashing on that block or any other one. It is a Poisson process, not a cumulative calculation.