For the OBDII hacks you can thank the EUSSR whose pro-competition regulations forced manufacturers to publish details of their protocols to the industry - which were bound to end up in the wrong hands.

The more recent emergence of radio boost thefts should be easy to mitigate with a software update, forcing the car to poll the fob more frequently and sound an alarm if the fob doesn't respond. However - for safety reasons engine shutdowns couldn't be forced and fob batteries would require frequent replacement. As someone else has mentioned, a faraday cage for your fobs is the answer to this one!

Not sure I get this. "Sound an alarm if the fob does not respond."

What if the fob is out of range? That would mean car alarms going off every time people went shopping.

Not sure I do as the 256 bit coder would just need resyncing to the car if the buttons were pressed enough times, what it needs is a double lock system which needs two presses to disable like some cars do to lock

that couldnt be replicated using signal booster as it cant replicate the two presses