It's hard to code into the game, I read it somewhere, it was something about how TPT can't calculate something that will happen 2x or 3x the speed.... :/ Long story short, its hard to code and will make it extremely lagggggy
The problem is that it would require two or three times the calculations in the same amount of time. It is extremely hard to predict what something will be like three frames into the future, and it requires you to calculate all the steps that lead to it.