Building my own toolset and curriculum is exactly what I want to avoid.
1) Everyone has basically the same problem (learning a language).
2) Many people are building their own tools.
3) Most people are dissatisfied with the tools available.
I have a hard time believing that there is no more efficient way possible than conversing with native speakers as one commenter seemed to suggest.
I also don’t believe the “procrastination” suggestion. My girlfriend has worked through the entire path on Duolingo Spanish. She can’t speak Spanish.
In my experience living abroad, the fact that so many people speak pretty good English is both a blessing and a curse. We could have a conversation in French but it’d be pretty boring. So my friends and I always speak in English but I don’t get better at French.