It is possible for any car manufacturer to make their vehicles virtually un-break-in-able. I say virtually as an angle grinder doesn’t count as a fair test in making a vehicle un-stealable.
Rolling door entry codes, unbreakable glazing, reinforced door framing, shoot bolts, shielded locks to prevent piercing access etc go a long way to holding up a vehicle theft, but this causes its own problems. If a car is so secure, how do rescuers get in when you crash. It’s a trade off between security and safety, as crumple zones become further stressed by the extra reinforcements, so this makes the design less feasible.
In later years it was the quest for fancy gimmicks like keyless start/keyless entry etc that made our vehicles more vulnerable to less damaging hacking technology, although keyless entry can be deactivated. What’s wrong with the good old hidden kill switch, or fitting a Ghost as standard. 
Rolling codes is crackable. And all Omegas, VAGs more than a few years old, and just about everything out there was cracked, and tools were readily available that just needed to catcher the code of one key and it would be able to send the next 1000s of codes.
Thing is, nobody wanted to nick an Omega (or VAG product)

And electronic security relies on some for of predictable encryption, and that's its weakness, that will always be a never ending circle, as ultimately its the future, probably tied with biometrics. Mechanical encryption is usually breakable, which is how safe breakers make their money

. Current biometric security is frequently flawed as anyone with biometric security on their phone knows.