Sure some miners are better situated (cheaper power, cheaper cooling, better hardware, etc.) so they are more profitable than other miners.
You are assuming:
1. That supply of for example cheaper power (and other similar resources) is unlimited and instantly available
2. That supply of more efficient miners is unlmiited
3. That more efficient miners can be deployed instantly before even more efficient miners are developed.
All of these are false.
Looking at averages for the entire network is incorrect except in the static model where there are no constraints (time or quantity) on increasing capacity.
Sure in that toy model the most efficient miner just instantly scales up to cover the entire network and then the averages do apply.
This is also totally unrealistic.