The true data rates (see my other posts) are most likely around 5-10 MB/s. Which is so low the benefits out weigh the costs. After all, what if their is an issue with the software? How are you going to reproduce without the logs, especially on a R&D system like Google has (yes it's still R&D, they can't even drive in the rain).
Your "true data rate" is completely wrong. You have no idea at what frequency they are converting analog to digital signals. You don't know for sure they are using off the shelf sensors. Your ignoring data sources in your calculations like OBD from the ECU or even GPS and AGPS data. etc etc.
