I’m not really surprised about this.
Those have never been used much, and the last 20 year or so anything “high density” is SMT stuff.
However, it’s very easy in KiCad to make your own footprint. There are even a bunch of wizards in KiCad to make footprints.
The only problem is with the library management, which has a few pitfalls.
Before you can create your own footprint, you must create an (empty) library in a writable location.
(KiCad’s default libraries are not writable for users).
You must also add your library to the library search list in PcbNew.
Creating the footprint it’self is trivial with the wizard:
Then in the Footprint wizard for S-Dip simply enter values for pad count, pitch, etc.
But for more details, follow Rene’s link.