I'm willing to back up my statements with my existing login, and I don't need to be an engineer to read the history of resuable launch systems. They've been around since the 1960s, and space-capable launch systems were a thing in the 1980s. They were killed the first time around by the collapse of the USSR, and then again when the Iridium went bankrupt, eliminating the demand.
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.