Bathtub drain design - Fastest draining?

Seems to me that things are the way they are because they have always been that way!

Like shower heads installed at chin height! Or small bathtub drains which take forever to drain the tub...

I'm going to install a new bathtub, so....

Question 1: Do they make bathtubs with a larger diameter drain (Where to buy?), or are these all the same size? (If they don't, they should!)

Question 2: If I have to install a bathtub with the standard small drain, could I run this into a larger drain pipe and get faster draining of the tub? Or would it not matter?

Bathtubs and the drainage system to tubs were designed to drain at a
certain rate so as not to cause a large volume of water flow into the
drainage system.Other than very large soaking tub which may by 2".