The reason is because mobileye patented (US20080137908A1) it and won't let tesla use it.
If it's really due to a patent, that just makes it worse. Tesla has known all along that they can't deliver the product they sold.
FSD is literally improving exponentially, looking at it in Europe (where it is blocked by regulators with economic incentives to delay Tesla's progress) is like looking at a fully fueled rocket ship at ignition and complaining that it is not moving.
Go take a ride in a new Model Y with hardware 4 and V13 software in North America and you'll realize how the EU regulators are screwing over European customers.