Trying to get everything into std requires a lot of work that I think gets harder when considering Rust's goals of being low level and paying only for what you use. Not having finalised some aspects of the language itself would also slow this down even more.

I'd rather have libraries built with more freedom and the possibility of having experimental stuff around meanwhile the std worthy solution lands, and if things work fine without them in the standard library then it makes sense to keep them out.

Rust may be lacking an easier way to shop for recommended libraries for common problems. There should be a path to discover all the good and best libraries for each problem. crates.io takes a stab at having this information, but I think more handholding and some sort of community seal of approval is needed.

I'm not the OP here, but I did write the blog post. I have mixed thoughts on how much should be part of std. I think that what we're seeing is a class of library where we could see a new level introduced to open languages like rust that sits somewhere above std, but is maintained and blessed by a broader group than just the nebulous community. Rust's separation of std from no-std is a good example of tiers that I think we could see evolve. Another example in the same category as clap would be serde and some of the specific serde implementations like serde-yaml that is now in a really painful unmaintained/forked status. Maybe these are things to push for more broadly in the rust community.

Yeah I was a little surprised to discover the standard library doesn't even include regex. That's kind of extreme. Even most C environments have that.