This has been my experience with Unity as well. You can spin something up super fast but actually tightening the screws and getting every little last bug out a

This has been my experience with Unity as well. You can spin something up super fast but actually tightening the screws and getting every little last bug out and getting all the little interactions between gameobjects working just right takes a really long time simply due to quirks and bugs that require odd workarounds. Unity is a wonderful prototyping tool but using it for production can be painful. That said I build engines for work so in my free time I like to just make games and using Unity for that purpose is refreshing and fun because the games I make in my spare time are simple enough that they rarely hit any limitations of the engine.