Our current age is not one of infinte plenty.
What this means if that if somehow we managed to make a classless society today, that after a certain amount of time it would start deteriating as the resources were drained. ( This is assuming that by redestributing the current resources that we have, we would not be able to generate more resources faster than they were used.)
Thus, something like the space station is essental, because then the human race isn't limited to the resources of the planet earth, but instead that of the universe. Indeed, its hard to say 'let people have hard times now', but a possible future is much worse. An example is: Weath is redistributed. Everyone is happy(*) In a certain amount of time, we realize that we need to get off earth, because we are running out of resources. We start a space program back up ( because it had been canceled before, because it was a waste of resources ), however we don't get it significantly advanced. We run out of resources. The Human Race is doomed to a slow long death.
The problem with resources is that if society was classless, how would scientists get the resouces they needed? There would be two ways of achieving this: having everyone agree that the scientists need much, much more than anyone else, which is unlikely, when as much as spent on scientists as it is now. The only other way to achieve that is a government, and with govenment you cannot have a classless society.
(*) This is the biggest part of a classless society.
If everyone is not happy, what is the point? All that has been done is take people that weren't happy and made them happy while others have been made unhappy.
Thus classless societies need infinite resources or else they will die.