That certainly seems like the idea for Tesla - collect all the data from the cars in real-world condition and use it for training. I think it's brilliant. Time will tell to see how well they can leverage that data. Having a better sensor suite would certainly make it easier though. It's a lot easier to interpret LIDAR (it basically makes a 3D map for you) than it is to interpret a camera (you have to figure out how to turn 2D into 3D).
My skepticism is in the leap towards a fully autonomous vehicle, safe for driving on real roads in harsh conditions. Very few people have attempted anything in bad weather yet, although Ford has actually done some work on it.
If we are talking about incremental improvements - sure that will happen constantly. What I'm saying is I don't believe you're going to get into a car without a driver anytime soon.