I think an important thing to
I think an important thing to note is also another statement made by Musk a few months ago. That the next generation batteries(Not sure if he meant the ones coming to the Roadster 400 mile or the Model 3 batteries) cost about 60-70$ per kwh in material costs. This leaves plenty of room to cut down costs as-is. Add in incremental improvements and most definitely 100$ per kwh can be reached.