We have consensus. That's enough. But the details will evolve. I don't think there's a silver bullet. A lot of small steps will make the difference. 

Furthermore, Bitcoin doesn't need to be used by every person on the planet. There is a minimum viable user base for bitcoin to fulfill its function, and currently no one really knows what that size will be. 

Either way, humanity as a whole will benefit, including people who do not have the privilege of interacting with the base.