Factory immobilizer was and still is the first wave of protection against vehicle theft. An opportunistic offender who is not equipped with the necessary tools usually cannot bypass the original vehicle immobilizer and your car remains in place, albeit damaged by forced entry, but still yours.
However, the situation is completely different if the offender is a professional and is properly equipped to perform his “work”. The factory-installed immobilizer also works in thousands of vehicles, so it is not a problem for the perpetrator to study the system perfectly and then get around it in a few seconds.