I'm afraid the majority of misunderstanding is coming from you.
So let's break down what vertical farming can really do.
1. Land which is zoned for agricultural purposes in many places where people live is not cheap simply because of development costs (desert, mountains.) Sure the land is cheap, but getting it into a usable state for farming is not. So being able to maximize what you can produce in one area is quite a necessity. To boot, buildings tend to be a little easier to manage when it comes to pest control and waste products.
2. The sun is horribly inefficient, contributes to a huge amount of water waste, and single-layer crop growth is inefficient as well for our growing global population. You're actually better off growing plants with LEDs (and in some cases the crop doesn't need light at all) using harvested solar energy.
3. Shipping is cheap LOCALLY. Try moving anything of any reasonable bulk anywhere more than a few miles and the prices jack up rapidly, plus now you're spewing pollution all over the place transporting things that could've been grown locally in tiny buildings.
"I actually love the idea of hydroponics for another reason entirely: it saves a ton of water."
Not always. Evaporation losses and transpiration/respiration losses are actually greater in some crops when it comes to hydroponics (as an example, a single cannabis plant can blow through gallons of nutrient solution daily in hydro while maybe using half as much in soil or a soil-less medium.) I think you're mixing up hydroponics with vertical farming in various places and really messing up the facts.
https://www.youtube.com/watch?v=9ZTikdxj8AI - Check this out. This is the very building I worked upon in the UK during my stay out there. There are tens like it across the globe feeding starving populations in extremely difficult conditions (growing more than grass.) Vertical does what your traditional agriculture simply cannot do - high-volume production with scarce resources in a tightly-controlled and environmentally-friendly space, in places where such things are generally impossible.
Next place I'm gunning for an installtion - Antarctica.