Yes, for me it might be one of the greatest achievements of humanity, but for the people paying for the show all of that work was for one thing and one thing only; to claim the high ground swiftly and decisively before the enemy. For anyone with the ability to put a capsule into orbit and to retrieve it, also possessed the ability to spy on the other party, safely launch and drop a nuclear warhead into the other party's major cities, and one-up the enemy in a show of technical prowess and strength - something that would persuade those on the fence to pick the right side if it were. That's what these programs were sadly all about and that's why they were ended once the high ground was decisively seized.
The reason why there isn't an Apollo-esque or Manhattan-esque thrust towards landing on Mars is because there is no substantial tactical, economic, or political advantage to be gained from the act. Sure in the long term there will be amazing pay-offs if we open up the solar system and expand outwards, but right now in the minds of the people who are actually cutting the cheques that pay-off is too distant, too abstract, too foolhardy, and too unsettling to justify any kind of support.
Now some people choose to rue the cause behind our current Earth-bound civilization, but I think this is actually a good thing. It ensures that when we do manage to find a way to reach out to the stars we will do it for the right reasons and our exploration will continue from one frontier to another because of that fact.