NASA is reverse engineering an old staged combustion engine. It is good of course, building a computer model, test firing the turbo-pump ... fun learning exercise ... leading nowhere (cheese shop?) While Musk has produced a new from scratch staged combustion engine and is working on full flow stage combustion. Because Musk's enterprise has specific goal, like actually flying to space where is NASA doesn't have such (NASA produced F1 when they did have real goal :).