You've discovered a lot of Google X technologies because it is a deliberate strategy by Google to publicize these projects regardless if they will ever reach a commercial stage.
They are attempting to stay relevant and perceived to be an innovative company in the eyes of their various stakeholders (employees, potential employees, shareholders, tech press, the general public, regulators, etc.) while transitioning to today's Microsoft.
... and when they stop, we can swoon over the tech advances of the new player. The fact that Bell Labs no longer puts out tech hardly detracts from their contributions.
They are attempting to stay relevant and perceived to be an innovative company in the eyes of their various stakeholders (employees, potential employees, shareholders, tech press, the general public, regulators, etc.) while transitioning to today's Microsoft.