Policy change that requires the manufacturer to install a part (that is a $~200 option in the USA) would have practically eliminated the car as being a "target" object.
Getting caught is always secondary in consideration to reward. If somebody is desperate enough, then it doesn't matter how risky it is.
Car theft isn't new. There being a punishment for stealing cars isn't new. What makes the Kia/Hyundia situation so significant is how EASY it is to do. Make it more hard to steal, and make that a mandatory policy.
The thieves will find other ways to steal cars, but it might stop the easy theft. More cops won't do that.