While I generally agree with the thrust of your argument. Farmers maximize profit not yields, as those are rarely the same thing.
Farmers have poor leverage on produce retail prices, and depending on the soil and climate they have, the local markets and distributors, a limited range of crops is available. Once chosen, they simply maximize yield.
As for permanent crops, farmers simply maximize yield.
More realistic examples are Center Pivot Irrigation Systems which don’t utilize all available land. https://extension.uga.edu/publications/detail.html?number=B8...
And central pivot irrigation increases total production, and average yields as well, when the alternative is rainfall.
Many central pivots near me have permanent crops in most of the corners, usually with drip irrigation. Also worthy of notice is not all land lots are neat squares, and some corners end up being quite small.
In areas with high average rainfall central pivot are often not supplemented by other irrigation systems or different crops. Sure, drip could increase yields slightly, but it’s not considered to be worth both the expense and hassle.
In other words, standard agricultural practice varies by location to maximize profit by increasing yield, when it’s cost effective to do so.
PS: Posting that feels like a really nitpicking argument as I think we both agree with what’s going on. But, I get annoyed when people talk about maximizing yield as a shorthand for maximizing profit. It’s something of a social convention where you can’t say you’re trying to make more money even when talking about how you make more money.