That's why rundown, dilapidated, etc "homes" in the Bay Area are so expensive. You're paying for the land. So a $20k home is still going to cost you a stupid amount.
If you go out to the middle of nowhere, you can get huge, and amazing, homes for less that $100k (because no one wants to live there).
Median home prices in flyover country start at $100K (West Virginia) and max out around $300K (Colorado, Nevada, etc.). "Huge and amazing" is probably 3x that.
In flyover country, the land is pretty close to free and typically you can buy the house at a discount to what it would cost to rebuild the same structure.
I'm guessing the issue here isn't that these techniques are innovative, it's that they've done their homework and the tolerances are tighter. If you construct them properly, they're more than sufficient. Emphasis on if. An inspector can't just walk in and eyeball something using his 30 years of experience to judge adequacy.[1] That's the problem--the classic tradeoff between administrative efficiency vs accuracy.
[1] The irony is that an inspector circa 1950 probably would have been able to do that.
Also the scale of the projects allow it to serve as a thesis project for Architecture students.
$2,300 does still seem high for that, though. I would love to see that broken down.