It's still not entirely clear why???It's still not entirely clear why Apple got rid of 3D Touch, but it has been speculated that Apple eliminated it in order to bring gesture parity to the iPhone and the iPad.
Of course it's clear! The force touch compatible display was more expensive and thicker than a standard display panel. They removed the feature to reduce production costs and to free up internal space for other components. And they replaced the feature by another one who is not 99% but mostly the same. Win win. And yes, I miss 3D Touch.