> Starting with absolutely nothing but a compiler

I don't understand what you mean by this -- Defold has a graphical editor?

> If Defold developers had produced a fraction of the libraries that Godot has, it might have had a chance.

What do you mean by libraries in this context? It has a robust plugin system with a reasonably active ecosystem, if that's the sort of thing you're talking about: https://defold.com/assets/

And it covers all the systems one would expect in a 2D game engine natively -- tilemaps, physics etc.

> As of now, it's worse than other abandoned engines like Solar2D (was CoronaSDK) for people entering the space.

I definitely disagree with this -- it's certainly not abandoned, and though it does have a slightly steeper learning curve than Godot or other popular engines, that's also how it gets such impressive performance and slim builds; feature, not a bug.