[mongol]

I don't doubt that. But which Linux distributions would support it? Red Hat I am sure. Perhaps OpenSuse. But any others?

[SAI_Peregrinus]

I can see NixOS doing similar things. It's all about declarative configuration.

Also very useful for embedded Linux distros, an A/B setup can help protect against update corruption due to power loss. If one of the two fails to boot, it can try the other, and retry the update.

[usr1106]

Does that matter? If the idea flies and someone does the work (maybe the opposite order) a new one could emerge.