We're not dependent on a single company in principle, but it so happened in the last 10 years, that they were the only one who cared and had the means to do something about it. Now that they've rekindled the interest and shown the way to lower launch costs, competitors are showing up. Which is good, but I still fear it's early enough that if SpaceX folded now, other space companies would follow, and we'd be stuck again in the early post-Shuttle era.

NASA, with its limited budget and constant micromanagement by politicians, doesn't want to be - and can't be - in the business of trucking things to orbit. That's why they're trying to outsource it as much as possible.