Money and lack of it.
They did land on the Moon. It was not a lie, American astronauts made the successful journey to the moon, landed and took home lots of moon rocks to prove their trip as authentic.
No other nations have went to the moon because there is no point to go back since we've already been there. Most space agencies would rather save their budgets for future manned missions to Mars and so fort.
There was 6 Moon Missions that landed on the lunar surface during the Apollo era.
None of these Apollo Moon Landing's were hoaxed.
I will discuss and disprove the conspiracy theories you may be familiar with.
Think about it logically;
The spacecrafts were definitely launched by NASA, which is difficult to fake.
Second the Apollo crafts could NOT have orbited the Earth for 8 days as some of the conspiracy theorists have claimed. If NASA had of done that they would have been caught on their lie, especially if they did it six times.
The Russians tracked the Apollo missions very closely and they knew for a fact that none of the missions were faked. If they only had the slightest clue that the Moon Landing was faked it would have been the ultimate propaganda weapon for use against the US and to Capitalism.
The flag waves because it was planted in the soil and Armstrong twisted the poles. This is obvious because in other footage you can see the flag is not moving when he walks past it.
There are no stars in the pictures because they were taken from the daylight side of the moon. Remember too there was no air to diffuse the star's light and thus they were incredibly dim on the lunar surface.
Also the reason there is no blast crater beneath Apollo 11 is because when the craft landed it reduced speed upon landing on the Moon's surface, so all that it did was blow away dust. The same is with driving into a car park because you don't drive in at 30 miles an hour.
The reason that there is a "C" on some of the rocks in the photos is because a crosshair got caught on the negative. This often happens, so I wouldn't worry too much about it.
Over 3 quarters of a million people were working on the project in total. It would have been impossible for every 1 of them to keep a secret.
Even filming the landing would have been MORE DIFFICULT than landing on the Moon itself. Think about the number of people they would have needed to shoot the Moon landing in a film studio.
Lastly if the Moon Landing was faked, we would have found out years ago. These things don't last 43 years without an answer.
All evidence given in my answer