I mean a lot of the stuff he's complaining about being crap aren’t exactly replaceable by the GNU coreutils.

People installed them on AIX/Solaris etc because the BSD/SysV tools they came with were basically abandoned. The GNU tools had a lot more useful features, not specifically more performant (although they probably were)

Sometimes they were faster but there certainly were more “bloated” - you can find people complaining about it from the era.

But they really did have tons of options and once you were used to them, you really wanted them.

But remember that GNU grew up in the era of multi-user systems; and Linux was the forefront of “personal computing Unix” where the user had root.