So, I had this crazy and exciting idea (personally) that if machines would be totally autonomous at this point, and able to work together no matter where, their construction power wouldn't have any limits and colonizing the oceans would make a lot of more sense.
The human being doesn't need to drive machines anymore, as they work as a single organism with flawless precision and reliability. We would have not only floating cars, but floating houses as well, giant coral and sea plants gardens and an endless aquarium looking out of the window.

Let's do this! :D