They do have cutting edge variations, such as Oregon cob. They also have old fashioned variations, that still exist and are used. And some of the cutting edge is old enough to feel a bit rusty. (Superadobe was invented before people knew about the problems of microplastics, for example.)

Hahahaha, centuries old techniques are now "cutting edge".

Yes, they are. You'll find that rammed earth [1] and cob buildings are used only at the cutting edge of expensive high design ecological buildings. Industrial building materials nearly wiped traditional methods of home building off the face of the developed world.

We are in many ways rediscovering older methods and techniques of building, especially in materials.

Also Consider SuperAdobe [2], which uses nothing but dirt onsite and plastic bags.

1. https://www.dwell.com/article/modern-rammed-earth-homes-723d...

2. https://www.calearth.org/intro-superadobe

I'd argue that cob in particular spans across the range from build-it-yourself Womble homes to fancy schmancy eco-bourgeois. And that it's mainly access to land and planning permission that's blocking the former (or causing them to be bulldozed by busybodies). It genuinely is one of the rare few building materials that can be prepared from materials on site and put up by amateurs.