Nitpick: A high-end Ferrari (and other high end supercars) is well in the millions. You aren't going to see these at your local showroom because they aren't available. They are only offered to folks that already own Ferraris and are Ferrari enthusiasts.

For example - Bill Gates could not buy a Ferrari LeFerrari (from the factory) because they would not sell it. Obviously there is a healthy second hand market - which Ferrari also tries to limit.

https://www.wired.com/2014/10/herjavec-ferrari-laferrari/

(EDIT: Better article)

I was just using the price range provided when I google "ferrari price". The number range passed a sniff test so I picked the highest one and ran with it.

Your numbers and sources are clearly better.

Are there even 10,000 of those "hyper-cars" out there to be bought?

10,000 "brand new" cars available in 2017? I don't think so. 10,000 models ever made? probably.

Generally these cars are very limited production runs starting at 500 examples for the "common" ones (seriously) down to single digit numbers models for the very very exclusive ones. The Lamborghini Veneno Roadster is a recent example: http://www.roadandtrack.com/new-cars/g4107/lamborghini-venen...