"Farmers, Indies, Oilers, and to a lesser extent, Cashers, all have far superior production when a significant portion of their land is unbuilt."

So a casher with 15Ka, a percentage of which are unbuilt, will cash at a higher rate than a casher will 95% res & EZ and 5% ICs (assuming both have maximum res and bus techs)?

Indies, too? I have always thought that to be most efficient the indies and cashers has to produce at a maximum levels, which to me means all acres occupied by production buildings for the respective strategy.

That section is talking about a Dict Techer.

The sentence would be more specific if it said "COMPARED WITH A TECHER, Farmers, Indies, Oilers, and to a lesser extent, Cashers, all have far superior production when a significant portion of their land is unbuilt."