I would bet that more than 0% of that perception, at least from developers, comes from how _fucking awful_ the Unity editor is. It's one of the worst pieces of software I've ever used. The games you can make with Unity are absolutely very impressive, but the tools Unity provides are just awful, and give a lot of newbie developers the perception that Unity is a hacked together pile of garbage (which...it is, but so are all game engines). Godot, Unreal, and GameMaker are, I would say, the main competitors to Unity in the Indie space, and all three of them have much higher quality editors than Unity's.