Why are Judo's Seiryoku Zen'yo Kokumin Taiiku exercises seldomly practiced?

In Kodokan Judo by Jigoro Kano (the founder of judo), chapter 19 Seiryoku Zen’yo Kokumin Taiiku contains a catalogue of individual striking exercises called Tandoku Renshu and partner exercises called Sotai Renshu. This is Kano’s description:

a system of physical education ideally possesses three characteristics: it promotes the development of strong, healthy minds and bodies, is interesting, and is useful. Not only does Seiryoku Zen’yo Kokumin Taiiku meet all three requirements admirably, it goes well beyond being merely gymnastics or simply a martial art.

This kata consists of two groups of exercises. One is practiced alone, the other with a partner. All but one of the exercises have direct applications in self-defense.

The seven partner kata are all present in the promotion requirements for dan ranks, but Seiryoku Zen’yo Kokumin Taiiku is not. I have never seen it practiced in a judo context, either for physical development or martial purposes. Aside from the ukemi (falling) exercises, the Tandoku Renshu are the only solo exercises in the book, which presumably would make them valuable during times when partners are not available.

Why is this original content from the founder ignored, despite it being in one of the most popular judo books available?