Learning about a language is different from acquiring a language, Krashen et. all has a lot of research on how people actually gain fluency. What most people are doing with language learning is like learning "about" chess, not learning to "play" chess. It's why you have people in China, Japan with seven years of English and they can't engage in simple conversation, or likewise people in the US, UK with seven years of Spanish and have trouble asking for anything beyond where is the library.
This is a great read (worth reading it all if you're really interested in acquiring a second language as an adult) about a guy who taught himself French as an adult to a high level of fluency via only watching TV and radio: