The law of large numbers only applies to a random sampling. There is very clear indications that targeted disenfranchisement has been applied to the American electorate for decades. This indicates that if more people had voted, or been allowed to vote, that the results would have changed, or at least that’s the belief of those who set things up this way. Those who aren’t voting due to apathy may or may not be represented accurately by the votes cast, depending on the cause of their apathy.