"And why is this even a concern for a game started in 2011? It's mind boggling that they are making these kind of decisions 6 years into development, surely just finishing the damn gameplay should be the focus?"

Well, I would say, it is not a ordinary game. And even though I don't know about their Engine, but normally it should be possible to make those changes on the engine without any effect for the gameplay, since they wanted to support OpenGL before.