There is actually a reasonable amount of competition within the autonomous car space. A lot of people online only ever hear about Google's initiatives, but Audi, BMW et al. are building driving systems, some of which approach 100+ km/h.[1]
I definitely agree that more competition in the area is good. Hopefully as more players build these systems, they'll continue to improve and be commercialized quicker.
That's why I added "obvious", because even though there are a lot of autonomous efforts (large and small) from other companies, Google seems to be getting all of the attention.
Actually, several manufacturers have self-driving car projects[1]. some of them are even field-testing them in real-life situations, such as a driven leader truck being followed by other trucks[2].
So, I don't think it lacks competition for Google, who doesn't even build their cars - most probably they'll license the technology for other companies, and Tesla may well be one of them.
Google will put a markup on licensing. If Tesla owns technology and produces it, they can a) have it free for their own cars, b) license it out and compete with Google's pricing. Tesla's model is so successful because they keep everything in-house, therefore there aren't tons of profit layers added onto production and distribution.
I can't wait for the autonomous car manufacturers to start suing the crap out of each other for patent infringement. And by "can't wait for" I mean "dread".
Google probably has close to a million miles of self-driving car experience by now, Tesla is several years behind Google in this field.
I'd be willing to bet that they were planning some sort of partnership. This isn't a technology that you want to get wrong, and once other vehicle manufacturers start offering a comparable electric car (soon) then Tesla will need to have something to differentiate themselves.