Architect's Dream House: Less Than 200 Square Feet

That's part of the push.

There's also a lot of influence from real estate developers, financiers, and the like, to produce a, hate the word but it fits, "product" which will entice purchasers.

Much of the construction materials and standards are of the bare minimum to pass inspection. If you're in the trades you'll hear terms for wall blocks (the horizontal pieces placed between studs) depending on whether they're attached with one or two nails per end (the latter is marginally more expensive, but more robust), the thickness of studs, type of sheeting used, etc. Notably, contractor friends when building their own home significantly upgraded construction standards from code with an aim toward longevity and robustness.

The principles behind Earthships (and other sustainable designs) are to, generally, minimize both environmental impacts (through locally sourced and recycled materials) and ownership costs (through passive heating and cooling, water collection and reuse, etc.). Earthship Biotecture discusses the motives and evolution of their designs:

http://earthship.com/a-brief-history-of-earthships

The key principles:

⚫ A structure built from largely recycled materials

⚫ Heating and cooling

⚫ Electrical system

⚫ Water harvest system

⚫ Contained on site sewage treatment system

⚫ Food production

The designs (or variations on it) are used in a wide range of climates, from alpine to desert to tropical to temperate.

As for the pest-resistance -- rodents and insects aren't unheard of in modern and/or traditional construction either, though it would be interesting to get a direct comparison of the Earthship vs. more conventional designs in similar areas.

You asked a question. I answered it based on both 1) my direct experience with construction and constructions standards and 2) material which is directly viewable on Earthship Biotechture's website.

As I stated above: I've known of the general concept for years (decades -- first heard about "junk houses" in the 1970s), but really only started revisiting it in the past year or so. And I'm genuinely interested in what the negatives of the design are.

I'm also generally somewhat skeptical of alternative concepts. Widely used designs are, if not always ideal, at least generally well understood particularly in their shortcomings and/or failure modes. And a lot of alternative concepts tend to be oversold, especially by their creators and proponents (and Reynolds is nothing if not a crusader).

If you're interested in the evolution of housing, it's helpful to realize that there's a vast diversity of designs applied to many different locales. Much of the variance is due to local needs, materials, costs, and capabilities. E.g., building with loose or lightly mortared stone and mud brick is cheap, but not particularly proof against earthquakes.

If you'll travel across the US, you'll find very, very similar designs being built independent of climate or location. I could speculate on specifically why, but a huge level of concentration in the homebuilding industry likely has a great deal to do with this. I'm also well-acquainted with fairly recent construction which has fared poorly even in only a few years, hence my comments on construction quality.