On the contrary, lots of people enjoy the reinventing the wheel part as a means of avoiding all the tricky creative choices and risk of actually shipping a completed game.
Of course - sometimes you just need to learn how it works below, but if your goal is to ship, and you don't have a lot of time, then what I said strikes true to me.
I think this is also true beyond games, e.g. for all the different UI libraries.
I think a lot of developers lean on ideological angles to deflect rational criticism of their lack of progress and direction.
Unity and Unreal are absolute powerhouses if you have an actual idea and a burning desire to express it as quickly as possible to as many customers as possible.
If your game idea fits well into the structure of these engines: perhaps.
But I can tell you that lot of ideas that I have for games ("games" is to be understood in a somewhat more broader sense) don't fit these structures well. So I am very certain that for the game ideas that I have in mind, writing an own game engine would very likely be the better choice.