I dont see what it matters as far a farm size. If you have 1 miner thats not profitable. It wouldnt matter if you have 100 miners. If one isnt profitable then 100 isnt profitable. So huge farms have big overhead to factor into the price. If anything I would think they are more at risk of dying off than us smaller miners.
You're right, and a lot of people have a hard time grasping this it seems. The only advantage that a larger operation might have is cheaper electricity. However, that in and of itself is not impacted by the amount of miners in operation. It's just that people with cheap electricity use that opportunity to run a lot of miners. Large operations have significant overhead like rent and the cost of running an HVAC system. If you do it in a house you already own in your basement that cools itself, that's as cheap as it gets.