Yes, I made this comment because sometimes I see some devs calling Unity an ECS (although it has an ECS option, but that's not the default mode most unity games uses).
Just to say that ECS is not the only composition option: Entity with composed behaviors is also an option (and the most traditional one I believe), and it does not have the infamous complexity of "pure" ECS in my opinion.
Also, I think it's important to say that ECS is not the only composition option, you can just use "EC" (or also CES): while on ECS the behavior runs on systems, on "EC"/"CES" the behavior runs on components, which is the case on Unity (by default) and O3DE.
I believe the mentioned Scott Bilas famous talk about composition follows this "EC" model instead of ECS, except that he calls it Game Object instead of Entity.
His "Sensible ECS" is basically what I did on my (simple 2D) game, just simple structs with components, and functions that operates on these components.
That works well, although it does not features parallelism, but still managed to run on a old laptop that can at most run Windows 7.
That's because they share a common origin from Typed Lua and Titan languages:
https://teal-language.org/book/other_projects.html