Nevertheless, most Linux distros come with a threaded perl these days.

Of course. Otherwise, they'll have to field complaints that threaded applications won't work.

Whenever distro makers have to make a choice of "going for performance" or "going for broadest usage", they'll pick most of the times the latter. That will be more useful for most of their users, and hence, themselves.

Having said that, I often compile my own perls. On my home boxes, and on all work boxes where perl performance, version, and/or configuration is important.