If you're a zsh user it offers a version of something like xargs in zargs¹. As the documentation shows it can be really quite powerful in part because of zsh's excellent globbing facilities, and I think without that support it wouldn't be all that useful as a built-in.
I'd also perhaps argue that the reason we don't want xargs to be a built-in is precisely because of zargs and the point in your second paragraph. If it was built-in it would no doubt be obscenely different in each shell, and five decades later a standard that no one follows would eventually specify its behaviour ;)
I'd also perhaps argue that the reason we don't want xargs to be a built-in is precisely because of zargs and the point in your second paragraph. If it was built-in it would no doubt be obscenely different in each shell, and five decades later a standard that no one follows would eventually specify its behaviour ;)
¹ https://zsh.sourceforge.io/Doc/Release/User-Contributions.ht... - search for "zargs", it has no anchor. Sorry.