> There's a difference between something being provent theoretically possible in a laboratory environment and actually making it out in the real world.

Fingerprinting using IP address, running scripts, canvas fingerprinting, using installed fonts, and checking what resources are cached/blocked are all things that are being widely used in many websites, and are not just "theoretically possible".

They are even being sold as a product and are used by many companies.

Look at their customers - https://fingerprint.com/ .