It's a lot easier to go from a stage that lands to one that has to be ditched than the opposite. Worst case, Musk has the same tech that the rest of the world does, although to me it's clear he has quite an advantage.
Oh yeah and personally I think that it's going to work but it hasn't been actually shown that it's cheaper and that the rockets can safely be reused. And that really won't be well shown until multiple reused rockets have been launched.
