Item 2: The Saturn V delivered massive amounts of brute power. It had a throw-weight of 118 tons. This meant that it could push into low Earth orbit, a mass equivalent to two Mack container trucks with trailers. Or, if you want an equivalent mass of military hardware, the Saturn V could loft an M1A2 Abrams and two Stryker MGS systems into low Earth orbit together. Not difficult to get three men to the Moon when you have that sort of heavy lifting power at your disposal.
Item 3: There were enough brave men willing to take part in the flight. The Apollo 1 incident taught us much about the risks they were facing.
Item 4: A lot of people co-operated, with determination and resolve, to get the job done.
Item 5: The Apollo missions had payoffs for other, rather more sinister programmes, such as the ICBM programme. Which is one reason why the design details for the Saturn V reside in a secure warehouse under armed guard, because the US government doesn't want anyone else to be able to work out how to build a missile with a 118 ton throw weight. Doing so would enable in turn the construction of a multi-orbital warhead delivery platform that could rain down over 1,000 warheads on a target continent. While the nuclear powers haven't adopted a "many eggs in one basket" approach of this sort, just being able to build one such system and launch it successfully is a very scary prospect. The US Air Force was probably toying with a delivery system of this very sort, until they worked out that a Saturn V would be a very conspicuous piece of hardware, needing a vast silo. Even so, the thought of this being the ultimate MIRV dispenser wasn't that far from their minds.
That's just the items I can think of off the top of my head.
