Let me ask you a question. What do you consider mass adoption? We can't achieve that as third world countries don't have proper internet connections to use Bitcoin. We can achieve an immense growth in third world countries as they can benefit the most from Bitcoin. Reaching all these people may cost 10 years, if not more.
I guess what I consider mass adoption is adopted in the way the internet or cell phones have been adopted. Yes there are many people around the world who don't even have basic internet connections still but the proliferation in the 1st world is obvious to them they want and need to get on the train eventually.
I've just always made the argument if Bitcoin is supposed to be this revolutionary thing then the marketcap can't stay too low forever before it risks fading out as a fad.
Ok, now the question is, how long did it take cell phones or Internet to conquest the world?
Internet started in the end of 60s and pretty much till mid-80s, it was purely inter-university network.
Cell phones started with the first generation, fully analog back then in the beginning of 80s.
So in each case about thirty years in which our life has changed significantly. The initial ideas had undergone many changes since then as well!
Bitcoin has been launched in the end of 2009, meaning we have merely six years since its inception.
That leaves us with quite some time to get to the mass adoption. There are also several problems yet to be solved, like, e.g., make it light-weight enough so that the people who have no idea about block chain would be able to pay for their groceries.