That was because the base model of those vehicles didn't have an immobilizer like every other car on the market as a cost cutting measure. They also have ignition switches that are relatively trivial to bypass.
It's possible that some other manufacturer may try it again in the future, but the hit to Hyundai/Kia's reputation has been substantial.
> ignition switches that are relatively trivial to bypass.
The switches themselves aren't bypassed. Their design for the lock cylinder is so crappy that it can be snapped off, exposing the peg that actuates the switch.
It's possible that some other manufacturer may try it again in the future, but the hit to Hyundai/Kia's reputation has been substantial.