Not true... WiFi can be secure if it is designed to be. turning on the right level of authentication and using the right encryption can make it as secure as you want.
Hopefully it illustrates how important proper security design and implementation is... WiFi just happened to be the path that they used to get in, and one that Tesla left open... but this isn't the fault of WiFi, it is the fault of Tesla's security people in allowing access to critical components via that path.
Nope, not necessarily... though it does help by closing the door, leaving it on and securing things better would do as well.
Again, not necessarily. Sure, it can, if not handled correctly. but if done correctly, with encryption, authentication, and some intelligence, it can be a very secure transport medium.
In the end, WiFi is simply a means of communications. Yes, cutting off a means of accessing the car when driving is better security than leaving it there... the same way that turning off your cell phone is better security than leaving it on. Tesla (and EVERYONE out there who makes a thing that connects to the internet) needs to understand that they now need to consider security. And from my reading of their actions after the Keen attack they are paying more attention to that.
I am not saying that WiFi should immediately be turned back on, possibly they found another vulnerability and this is a short term protective measure, possibly they found that their architecture could not be isolated correctly from the WiFi system... but I think they do need to figure it out and re-enable it. Turning off WiFi is like unplugging your computer and putting it in a box after it was hacked. Yup, it wont get hacked again, but it's not very useful either. and we cant blame WiFi for that... it's your fault for not securing your systems correctly.