One of the reasons is Rust, but another reason is that the standard shied away from adding anything with frills because UNIX-likes run on all kinds of systems, many which don’t have space for this. There is a reason why something as seemingly ubiquitous as bash or vim are not available everywhere (but sh and vi are). The base set of utilities is really “do more with less” and the ability to keep to this philosophy means that I can connect to a router with 2 MB of MMC storage and still be able to have an extremely functional base set of tools, rather than having some arbitrary subset of the standard utilities because they just can’t be supported on platforms like that.