Communists in 1920: Oh, but that is because the Russians have to rebuild after the czars! Just wait five years, and Lenin will have everything in shape, and the Soviet Union will have the best factories, the best schools and universities, the best hospitals!
Communists in 1930: Yes, yes, Lenin got it wrong. But now Comrade Stalin has taken matters into his own hands, and in five years the Soviet Union will have the best ... etc.
Communists in 1940: Yes, Stalin was sabotaged by the counter-revolutionaries but now he's gotten rid of them and just wait five years...
Communists in 1950: Well, that was because of Hitler's invasion. Just wait five years and ...
Communists in 1960: Yes, well, Stalin was a tyrant. But now that Comrade Khrustjov is in charge, it is a matter of a few years - five at the most - before the Soviet Union has the best factories, the best etc...
Communists in 1970: Oh, but that is because Khrustjov failed where Bresjnev will succeed. Just wait five years and you'll see...
Communists in 1980: Give Bresjnev a chance... It's just a matter of a few years!
Communists in 1990: Oh, but that was because it wasn't real Socialism. Next time...