Flecs implements a relatively new programming paradigm "ECS". For context, here is a big budget project, Blizzard's Overwatch embracing ECS [1].

[1] https://www.youtube.com/watch?v=W3aieHjyNvw

Uhh it's not really new, I think it's been around for like 20 year-ish? Flecs though does bring new stuff to the table, for example relationships, which all the other ECS implementations do not.

True, I mean in relation to other paradigms, like OOP. It only really took of in the past decade.