They can collect some fraction of that data without 3G/LTE - but only from cars that are set up to connect to wifi (at the cost of on-car storage and additional latency to collect). Similarly, they could even collect data without wifi - e.g. collect data when the car is brought in for service.
Given this, in my opinion, the value of the data connection is disproportionately on the side of the consumer (updated nav maps, real time traffic, calendar integration, internet music, etc).
I speculate Tesla will charge for the connection after 4 years. It will be interesting to see if they give us the option to pay AT&T (or other service provider) directly for the data connection - in that case, the consumer would be paying for data used by the car to phone home and would be able to see the usage. Would be interesting to see how much data is phoned home!