Why is insurance higher with Ev's?
Because the insurance companies can get away with it.
The good news is that Tesla insurance should be cheaper for most drivers. It is now available just in a handful of states, but it will be gradually rolled out to all states in US and hopefully also to Canada.
As to your other question about the actual operational cost savings, use the supplied calculator. The more miles you drive, the quicker the ROI. In addition, you'll be saving on the maintenance. No oil and filter changes, less frequent brakes jobs, no belt re-tensioning, no spark plug changes, no radiator fluids and flushes, and more. Thousands of dollars saved over the life of the vehicle.
The autonomous driving option (various versions and capabilities by different brands) can make the travelling less tiring and save even your life.