Agreed 
The problem was actually the will to go further was NOT in fact there which was the main problem. Johnson wanted to keep "Apollo" going in the Apollo Applications Program but Congress wasn't interested. Congress was SPECIFICALLY not interested in allowing NASA to make or expect any MARS plans. The annoying fact that NASA, (who was aware of this "issue" but ignored it) tended to tie everything they spoke about for 'future' work into planning on going to Mars was not lost on them
-APP which would develop and expand Lunar and orbital work with an EYE TOWARDS FUTURE MISSIONS TO MARS.
DENIED
-A large Earth Orbiting Space Station which will be used to study Earth, Space Science, Biology and Microgravity with an EYE TOWARDS FUTURE MISSIONS TO MARS.
DENIED
-Nuclear and electric in-space propulsion which will enhance future missions with an EYE TOWARDS FUTURE MISSIONS TO MARS.
DENIED
(You may be sensing a pattern emerging from both sides here)
-A Space Shuttle to reduce the costs to getting to Earth orbit and back to the Earth, which can serve a future orbital Space Station and possibly with an EYE TOWARDS ....
SHUT UP AND BUILD A SHUTTLE
Ok, fine but we can use the Shuttle with an EYE ...
Don't MAKE me come down there and smack you... Again...
fine...
And the general public was fine with all this NOT happening because "space" was never very important to them in a personal sense anyway. And to go beyond the Moon in a big way you NEED the public to care and want it as a priority or at least among the top couple of priorities. That's never been the case though. There have been surges of interest such as in the late 50s with Colliers and Disney and then again in the late 70s with Space Solar Power and Space Colonies but it was never deep or broad enough to actually sustain momentum.
That's where the idea of "all we need is another Kennedy" falls down but the Space Cadet's (like me ) really don't get the underlying issues or the actual place space travel has in the public and political mind. Again even Kennedy had second thoughts about going to the Moon let alone anything else! He desperately searched for a way to 'match' the Soviets without committing to a major space effort and had he ANY other choice the US would not have committed to going to the Moon. Once he was assassinated it almost became politically impossible to reverse the decision* and Johnson (actually pretty correctly) saw it as a political tool and way to gain solid support from the South and West so no rocking the boat there. But as it drew towards the end he noted that Congressional and public support for keeping the program running were flagging and worst yet NASA itself didn't have a good plan for what to do after Apollo. NASA made no bones about their entire plan being "Apollo levels of funding and support continue forever with no questions asked" and Johnson (and many others outside and inside NASA to be fair) were aware this was anything BUT the case.
And then Apollo 1 happened. And in a politically dangerous move Johnson allowed NASA to investigate and correct itself rather than allowing Congress or an outside agency to do. Needless to say this peeved Congress to no end who were already tired of NASA's attitude and culture. (Lots of room to talk I know but keep in mind the ability to see in others what you ignore in yourself is a political survival trait ) And remember that "*" above where it was 'almost' impossible to reverse the decision?
You see there was likely enough support from the "martyrdom" of Kennedy to push through the Lunar landings on schedule but with Congress or an outside agency running the investigation and inquiry it was more likely that delays would happen. SERIOUS delays. Because it was also no secret that both NASA and industry were were not only writing checks they couldn't cover they were well AWARE they were doing so and had an unspoken agreement to not talk about it. (This picture is illustrative of my point this was done in all seriousness about the Apollo Capsule: https://en.wikipedia.org/wiki/Apollo_1#/media/File:A1prayer.jpg) Outsiders would MAKE them talk about it and the delay would likely push the first Moon landing well into the early 70s which would open up the idea that "well since we didn't make the goal and it's obvious the Russians aren't going either why bother?" as a very real and present possibility. Opponents were more than ready to use 'evidence' such as the Phillips Report (https://en.wikipedia.org/wiki/Phillips_Report) for just such a purpose if it could be done.
Johnson burned most of his remaining political capital, NASA and the lead contractors made several high profile firings and changes and Apollo 4 launched later that same year with an overall loss of only a few months from the schedule. But Congress now had pubic support and the ability to actually exercise their budget oversight to a more extreme degree and they used it.
Johnson had effectively lost the ability to control NASA's budget and future by the end of 1965, having effectively traded a majority of his political power to get the Great Society program rolling through Congress and the American public. Even if he manages to avoid the "forbidden subject" he still has to use his political resources to either advance the Space Program against a resistant and then hostile Congress and public or to push his Great Society program but it's unlikely he could do both.
Randy
