You won't be able to do this for instance with VAG cars that have KESSY. First of all the immobilizer is paired to the key, secondly the only way to pair a new key to it is via the manufacturer or a licensed dealership because you need a blob from their central server. But the consequence is that people feel like they are being fleeced when they need another key, because it can cost you hundreds of dollars to pair one.
In general these types of attacks are much harder in Europe where immobilizers have a legal minimum standard that manufacturers have to meet. On the other hand in the US immobilizer are entirely optional, which has famously led to KIA and Hyundai cars shipping without them and the Kia Boys TikTok phenomenon.
Because the ARE being fleeced. It's an artificial dependency on the vendor on the one hand versus a blatantly insecure approach on the other.
Secure pairing that can be done by the end user isn't rocket science.
