Newton's remark was mostly a backhanded slur against Hooke, as far as can be told. If you can point to some novel development in rocket fuel or rocket engine engineering of the 1950s that somehow contradicts my account, I am sure that I would be grateful of the correction. I wasn't alive then nor am I a particularly good scholar. But I did read Dr. Clark's book, which I understand to be the authoritative work on the subject, and the distinctions in the persons and nationalities involved in the periods in question do seem to be fairly distinct. Von Braun acknowledged the influence of Goddard explicitly, and the post-war and pre-Mercury/Apollo era of rocket science does seem to be quite an interesting one both scientifically and politically. As far as the fundamental science of rocket fuel goes, yes, there is unfortunately not much further to be done, but every science has noted limits to efficiency. But if I may repeat myself somewhat, the point was not that there had been prior art, but that nothing particularly important happened in the 1960s. There are only so many chemical reactions that are suitable for liquid fuel rocketry, and -- pertinent to the news event -- SpaceX is going down a very well-worn thermodynamic road with these rockets. So the impressive point, the reason that anyone is giving these people business, is not that they have any sort of greater chemistry-related insight than anyone else, but that they are planning on re-using enough components to drive launch costs down. But they haven't actually done that yet. They have yet to re-use anything but the barges. So perhaps in that sense, one could consider the achievements of the 60s and SpaceX to be equally lackluster, but otherwise it seems like a poor comparison.