Well you can see reports of people drag stripping teslas, and comparing speeds at 100 vs 90 vs 50% charge. Whatever the reason, you do slow down.

Apples to broccoli comparison. Besides what I mentioned being optional (I'm sure it has downsides, probably cost), comparing road legal cars with a supercar is... interesting.

You don't need a Tesla to figure this out, my toy RC monster truck does the same thing.