That's right, Goffredo. The current shape of the standard lib has a few experimental spots (String, Codable, protocols, ABI, others) that are under active evolution, guided by core "manifestos", implemented by narrower "proposals", where "better solutions" are constantly discussed and compared.
Some other kinds of "better solution" would require a near-complete redesign of large parts of the stack. Or a separate library (Large Proposal: Non-Standard Libraries). Which would require a tremendous team effort to match the quality of the current state of the ecosystem Swift has built so far.
The price of admission is, for understandable reasons, raising.