The different is Chrysler, and the rest of the established brands, don't have a clue about security. Researchers have already taken control of Prius systems, albeit with the need for initial physical access, and the Lexus Smart Access is easy to bypass etc.
Tesla have some well known security researchers now working for them, and the hackers noted that the security system in the Tesla vehicles is well designed. The OTA update hasn't been compromised, only signed code can be installed.