You have nothing to back up the statement that "reusable rockets are not a hard problem", and let me back up this claim of mine by pointing out that only partia

You have nothing to back up the statement that "reusable rockets are not a hard problem", and let me back up this claim of mine by pointing out that only partial reusability exists today. In addition I invite you to build reusable rocket systems, sir, since you have already claimed that the problem is "easy". You could make some good money solving that problem, and you would once and for all put this argument to bed.