Reddit reviews 4-Gauge Clear Black Ground Wire - 25 Ft. 4 AWG Gauge, Economy Oxygen-Free Copper Cable Wire w/ Flexible & Bendable Jacket, Translucent Matte Insulator, Chemical & Heat-Resistant - Pyramid RPB425

Lets pretend for a moment that this is the wire we are going to use (I know this is ridiculous for more than several reasons). So we have wire at $0.90/ft. We need.... ~3 miles so 5280ft x 3 x 0.90 = $14,256 in added cable cost (again these numbers like OPs are totally inaccurate)

I found an ad for 10 acres in California for $399,999 So 1 acre is assumed to be $39,999.90. (I have no Idea how reasonable this is I have only ever bought a lot in a small town)

So it turns out that land costs more than the additional cabling(of laughably made up price). So the next question is: can you fit more balloons on a plot of land than stationary units? Answer, probably. Airspace ownership is an unknown territory for me but it seems like you can fit as many balloons on your land as you can fit base stations.

So they are more productive and factoring in the cost of land may actually be more financially reasonable than you have indicated.

This all ignored maintenance costs. Why? Because average maintenance costs are UNKNOWN for the proposed system. Likely they will be more but how much more is not known.

I'm not saying you are wrong I tend to agree that short term it will be financially unrealistic but the problems this is designed to solve are beyond cost vs benefit. Those same problems may make the cost vs benefit favorable in the not so distant future.