Satoshi said, by 2020 bitcoin is eitheir mainstream either will disappear (quotation welcome, i didn't find it)
But how can it be mainstream with 7 transaction per second ? And if it's not mainstream, satoshi's logic woul tell us that
bitcoin will disappear by 2020 
Don't treat Satoshi's words as a prophecy. He was wrong about future of bitcoin himself, it is hard to predict future of invention so outstanding and new as bitcoin.
Total adoption could happen not in 2020 but instead 10, or 20 years later. As far I can tell bitcoin is not going to disappear in near future. That's for sure.