I get the arguments for this idea. Why did USSR play along? They (claim they) had all the same transmissions and everything else we did, and they called us to congratulate us. I guess they could have just made a wild guess, but it seems more likely that they ... observed us land on the moon before calling us to congratulate us on landing on the moon.
Likewise we observed all their unmanned flights, and our records for all this agree.
No, lies in fact can be easily kept , when they are institutionalized, and the people who know just die (from accidents and old age). The rest are labelled koooks and nobody believes them.
Read up on Project Manhattan and for how long it was kept secret and how many hundred thousand people were privy to bits of it, and it all kept humming along, and at one point drawing 1/3 of the all electricity power grid output in the state. Nobody spilled a bean to the great unknowing masses, until it was decided so, and even then, only parts were told in a very polished and streamlined "made for movies" narrative.