Here's why I think so:
Tesla is setting the correct expectations. Once the car is fully autonomous, the process of dispatching rides to a pickup location will be controlled by Tesla.
So, if you own the car, and but are not needing the car to be used for a week, the car becomes available on the Ridesharing Autonomous Network of Teslas (RANT :). At that point, it makes no sense to put the car on something like say Google / Uber autonomous networks of Ridesharing.
Its a bit like how iPhone is not open for non app store downloads and yet an iPhone buyer 'owns' the phone.
FWIW, every autonomous car maker will put their car on their own rideshare network (making a rider app is 1% of creating the ridesharing service effort). Uber and Lyft apps will become too expensive to use if they cannot figure out the autonomous vehicle part of the equation.