The effects are temporary. We are currently witnessing them evaporate, hence the increasing power of rightism.
What should have been done during the few decades when the temporary effects of leftist education had not yet evaporated was prohibiting rightists from reproducing, thus producing a relatively longer-lasting leftwards shift. But the mistaken belief that education alone would be enough was the very belief that caused the leftists to neglect this, hence the rightist resurgence now.