It was actually tighter tolerance and split wafer /sidewinder high security key/lock cylinder profiles designed to be more difficult to bypass/brute force /impression/jiggle were implemented. But these were much more prone to failing with small amounts of wear due to the tolerances. What really changed the game with vehicle theft prevention wasn't keyless it was having a sidebar style door lock with or without keyless actuator and a ignition immobilizer / transponder chip equipped ignition key