Imagine writing a program and you couldn't debug it fully because if it crashes someone would die. Autonomous spacecraft always were the 'easy' part, humans are the hard part.
In what you write, achieving the high safety of the mission itself seems the achievement to me, and not putting humans on it (just like we have self driving cars already, it was a great achievement, but now it's time to get them working with high safety. After that putting a human in them is a trivial step).
USSR has already landed a robotic mission (Luna 9) couple of years before and sent pictures from the Moon (https://www.space.com/35116-luna-9.html)
From purely technical standpoint it would be much easier to develop comparable robotic mission. Most of R&D was to develop stuff that would not be necessary for robotic mission.
That of course, is only purely technical standpoint. Sending a bundle of motors, sensors and wires to Moon is nowhere as rewarding and prestigious as sending actual humans.
Also sending a human without being able to return at least theoretically wouldn't have been ethical.
I think I read an article that described that humans were given tasks that would normally be given to computers just to keep them occupied. For some task it was just convenient as humans were already on board. Some tasks were given so that astronauts were in control of their lives, otherwise they could just as well be performed from the ground.
If you think about it, there is only 2s round trip time for signal from Earth to Moon. If the only thing astronauts do is sit in the cockpit, flip switches, type commands and maybe handle some kind of steering, the same thing could just as well be performed from Earth. There could of course be possibility for communication disruption but at the same time, with no actual people on board, less fallout from possible problems.
When it comes to landing things like keeping attitude and slowing down for touchdown are easily automated. Keeping attitude is what all rockets are designed to do. Slowing down for touchdown is also quite simple when you get precise distance to ground measurement and a human on Earth can point a relatively flat piece of ground to land on.
SpaceX booster landings are difficult because of couple extra requirements. First, it is in Earth gravity and dense atmosphere and from high speed. Second, boosters are very long necessitating perfect stability at landing. Third, they use what is called "suicide burn" which means that boosters basically coast until almost end where they break very hard with basically nil margin for error. But this is in the name of efficiency because every kg of fuel saved on landing as many, many more that could not be taken to orbit.
In other words, booster landing is very dynamic process.
Compared to that landing on Moon surface were pretty simple and with relatively large margin for error.
Landing on Moon surface could be done without large dynamic component like suicide burn. The craft can leisurely hover over the surface and touchdown with barely any speed. This is comparable to cheap quadcopter landing --keep your attitude straight, descend slowly loosing speed until it is zero at zero distance to ground.
But the Russians were able to achieve this a few years later with their moon rover. Although it was more of a dumb luck gravity drop, and hope you don’t land on a cliff, and topple over and die.
Then, the Chinese were able to do it, with an even more sophisticated robot, that was able to make automatic landing decisions like a human. This is the ultimate moon lander.
Given the choice between humans vs. robots, I’d take a robot any day, to land myself on the moon. You don’t have to worry about pesky humans making emotional life or death decisions in the heat of the moment, and jeopardizing your mission.
https://en.m.wikipedia.org/wiki/Luna_programme
NASA also landed Surveyor.
Lots looks to be 4 or 5 depending on how you count.
3 were killed due to a fire in the pure O2 atmosphere during testing of Apollo 1.
1 was killed while working with a high pressure water line on ground support equipment.
1 to be lunar module pilot was killed flying a fighter jet trainer between Cape Kennedy and Houston.
Not to take away from their sacrifices, and not to play down the amount that we've become more cautious, but I think it's an exaggeration to say that lots of people died.
Source: https://en.wikipedia.org/wiki/List_of_spaceflight-related_ac...
It's unfair to pin that on the Apollo program. Flying fighter jets is very dangerous, and pilots are put through a lot of rigorous training to handle it. Many died in those jets in routine flights, which that one was.
I guess there were probably other, non-astronaut deaths in the Apollo program, workers getting electrocuted or falling from gantries at contractors' manufacturing plants, but even if so, it's not renowned as an example of unsafe work conditions.
[0]: https://en.wikipedia.org/wiki/Luna_programme#Failed_missions