I work in gamedev, both on my own game in my free time, and professionally. Projects take years to develop, and Unity was doing pretty ok 6 years ago, when I started my own project. Will I make another one in Godot? Very probably yes, Unity sucks, but moving an existing project is unfeasible.

Another reasons are console ports. Getting a Unity game to run (run, not release/port completely, but that's an important step) on any console is pretty simple, since all the core libraries are prepared for you and you just include them. For Godot, you have to find someone who already has those libraries.

Unreal is too heavyweight for a lot of games. It's amazing if you want some kind of realistic-leaning 3D, but the project size and (editor) performance is a huge problem for smaller things. Still better in a lot of things compared to Unity, but it's also harder to get into, since it's C++. Unity with C# is way more approachable, especially for students with laptops, who can barely get the editor running (It was a reason why I barely finished my Unreal assignments on college, and stuck with Unity). So, you have a lot of people who grew up on Unity, making it easier to hire for it. And when you are used to one engine for most of your life, with years of experience that's limited to it, it is difficult to switch (although, almost everyone I talked to who works in Unity has "learn Godot" on their todo list)

I've been mostly seeing Unreal recently, when talking to other devs and studios at conferences, and not many new Unity projects. Anecdotal evidence, though.

Also, while I'll definitely use Godot for any future project (which I already did for some gamejams), I can't imagine maintaining a large AA(A) codebase written in GDscript. To be fair, it might be because I don't have any large-scale project python experience (which I also can't imagine writing a large app with), and IIRC the C# support isn't as good in Godot yet.

Yes. I can't port my projects easily and they'll be released for free anyway.

I don't think I can stomach coding in C++ again and Godot has grown but needs some time. I'm ok with waiting for now.