What a ridiculous take. Making a game engine is to games like building a camera is to making movies. Once a blue moon some new camera enables some new technique (the Matirx), but mostly people just use the tools that exist.
The same is true in games. Tons of super popular and successful games didn't write their own game engine and made both art and money.
I'm watching a friend, claiming he wants to make a game company, burn through all of this money instead making a game engine. If he succeeds, great! But I suspect he'll just run out of money before he's even started working on a game. If it was fun to make, great too. But I think he'll look back on it as throwing away an oppotunity.