>>I never heard of anyone handing in their gasoline car and picking it up a few days later with faster acceleration and longer range, just like Tesla now offers with their new battery.

It's really pretty standard. I have several friends who "chip-tuned" their diesel engines for significant HP boost, people regularly change suspension parts, exhausts, they add intercoolers to the engines, order a turbo etc. Those are pretty standard things and there are many specialized shops when you can drop your car for a few days to get those done.

You shouldn't trust your opinions on the topic if you haven't heard about it because those are really common things among car enthusiasts.