I think the size of the stdlib is a bit misplaced. If you look at many of the complaints, many of which I agree with, the real issue isn't whether something is part of the language distribution itself or provided externally. The problem is bloat in the dependency tree. Nobody wants to individually vet a thousand plus library authors and enterprise/government or just anyone who cares a lot about supply chain security is not likely to consider "number of downloads" on crates.io a reliable proxy of trustworthiness.

Large collections of libraries that can often be pulled in as a single dependency, like boost, apache-commons, or all of the C libraries provided for free by a GNU system, are a nice middle ground. They're trusted, large enterprises will let you use them, you don't need to separately download every single library, but the core language maintainers don't need to maintain these collections themselves and they don't have to be subject to hard backwards compatibility guarantees provided by a built-in std.

But, of course, that also means you can't ask the core language maintainers to create this for you. These are community efforts. Also, I don't believe any of them existed within 11 years of the language first being released. Curated, dependable library collections that become ubiquitous as part of a language ecosystem take time to come about.