A developer sharing is experience working with EFL:

https://what.thedailywtf.com/topic/15001/enlightened

It sounds like the guy is way overexaggerating and basically didn't understand the library he was working with. What he describes isn't anything special - the "Evas_Object" (aside of the weird name) sounds like a HWND in Windows or Window in X. The part about layouts sounds like similar to sizers in wxWidgets which are used so that you can avoid using heavyweight native widgets just for layout that some other toolkits do. The event callback sounds like it uses a generic messaging system - again not much different than something like WndProc in Windows.

EFL is written in C so it does have to work within the limitations of C but -non-toy- GUIs are inherently object oriented so things will be a bit more complicated than Qt that can lean on C++'s support for object oriented programming. Especially since apparently EFL also supports bindings to other languages which may also make things a bit more complicated.

It definitely struck a cord when I had have to use it in a project around five years ago.

Luckily I got an opportunity to a new project. And the company in question (Samsung) ultimately dropped it IIRC.

I ran Enlightement for maybe a month or two to try it. I mostly ran twm, fvwm, and similar at the time. Those are obviously not satisfactory for a typical user.

I gave it as an example of something which ran rather sophisticated theming/compositing/effects on hardware at least 2 orders of magnitude slower than today, and something which modern Ubuntu/Fedora struggle with.

I'd encourage you to compare the specs of the 3dfx Voodoo (the "magic dust") to even bottom-barrel integrated graphics of 2020.