It's a lot worse. A high quality project can have great documentation and guides that make it easy to use for a human, but an LLM won't until there's a lot of code and documents out there using it.
And if it's not already popular, that won't happen.
No, this doesn't ring true: long before there were LLMs, people were selecting languages and stacks because of the quality and depth of their community.
But also: there is a lot of Rust code out there! And a cubic fuckload of high-quality written material about the language, its idioms, and its libraries, many of which are pretty famous. I don't think this issue is as simple as it's being out to be.
Isn't this article an example of that. There might be a lot of rust code but if the apis are changing frequently it's all outdated and leads to unusable outputs.
And if it's not already popular, that won't happen.