>I like to compare them to the car sharing companies (like zipcar/car2go etc...) which managed to de-throne the entrenched rental agencies without going out of their way to break laws.

Except for the fact that Avis bought Zipcar. So not sure about the dethroning part.

I know some folks who really depend on short-term rentals to support being carless but it's a relatively niche service--especially with current Uber/Lyft pricing.