And a new OS needs to be significantly better than those to overcome the switching costs.
Erm...no? That's exactly what that means.
Earth-Ovens haven't been in widespread use for hundreds of years. People can still use them to bake bread however: https://www.youtube.com/watch?v=WAJqGVxuJPo
Feel like you are using a very narrow definition of "success" here. Is BSD not successful? It is deployed on 10s of millions of routers/firewalls/etc in addition to being the ancestor of both modern MacOS and PlaystationOS...
Who cares if nobody switches to it as their daily driver? The goal you proposed was "viable", not "widely used". The former is perfectly possible without LLMs (as history has proved), and the latter is unrelated to how you choose to make the OS.
Every single production OS, including the one you use right now, was made before LLMs even existed.
> What makes sense if that of course any LLM-generated code must be reviewed by a good programmer
The time of good programmers, especially ones working for free in their spare time on OSS projects, is a limited resource.
The ability to generate slop using LLMs, is effectively unlimited.
This discrepancy can only be resolved in one way: https://itsfoss.com/news/curl-ai-slop/