A strong advantage of that approach is that you don't need to be the core Rust team to do it. Anyone who wants to do this can just start doing it now.

I agree. Unfortunately, I think that a lot of the people who ask for a bigger standard library really just want (a) someone else to do the work (b) someone they can trust.

The people working on Rust are a finite (probably overextended!) set of people and you can't just add more work to their plate. "Just" making the standard library bigger is probably a non-starter.

I think it'd be great if some group of people took up the very hard work to curate a set of crates that everyone would use and provide a nice façade to them, completely outside of the Rust team umbrella. Then people can start using this Katamari crate to prove out the usefulness of it.

However, many people wouldn't use it. I wouldn't because I simply don't care and am happy adding my dependencies one-by-one with minimal feature sets. Others wouldn't because it doesn't have the mystical blessing/seal-of-approval of the Rust team.

lets put a price on it

The "Rust core team" should be working on the "Rust core", not every little thing that someone somewhere thinks should go in a standard library. It is part of the job of a "core team" to say "no".

A lot.

Like, a lot a lot a lot. Browse through any programming language that has an open issue tracker for all the closed proposals sometime. Individually, perhaps a whole bunch of good ideas. The union of them? Not so much.