Was political, when the Russians were in space first, (remember what JFK said they would be the first to WALK on the moon) the Americans wanted to be the first, but clearly the Russians had the technology ahead as they were already the first on the moon.
The Americans I believe staged their being on the moon so as to make it look more the great achiever than the Russians. So they haven't really bothered because there was no need, they were already accepted as the first to walk on the moon. Crapo