Thanks! Yeah, I recognize that's definitely a possible outcome. Perhaps it's statistically the most likely outcome. But I agree with you that it's worth doing if for nothing else to see what it's like. At worst, I go back to being an employee again somewhere.
At Google you got paid a great salary, had great 401k and perks to work on projects that most likely go nowhere.
Working for yourself you're sacrifcing all those perks, to work on projects that will most likely go nowhere.
That said, definitely do it. It will teach you a ton in the process, everyone should go out on their own, mostly to realize how hard it can be.
New perspectives are invaluable, so I applaud your decision and wish you all the luck in the world!