I think it mostly explained by that in earlier days most people who dived into programming did it because it interested them. Then it became one of most lucrative career path, and naturally it saw surge of people, who do not share same interests. Relative amount of people invested in dive bombing into meaty details dropped, but it quite possible that absolute amount have not declined by much.

Sekiro is the closest reference I know, but it is still quite different. Sekiro most important part is bosses, and I doubt En Garde will provide same variety (And if it against all odds proves me wrong it probably gonna become my new fav game). On the other hand En Garde focuses more on combat with regular enemies, and IMO does it better then other games with similar gameplay.