The last comment provoked some thoughts which probably warrant a new post. What is the relation of truth/value and popularity? The impulsive answer is none at all; indeed, the very test of moral integrity resides in its indifference to polls, in political terms. However, I don't know that it's that simple.
It's obvious that physical/scientific truth bears no relation to popularity; if global warming is primarily the result of human activities, this will be the case even if only 5% of the population believes it to be so. In contrast, I would suggest that advocates of both moral and aesthetic truth do aspire to majority confirmation, but crucially over the (very) long term.
I think it was the ancient Greek Solon who reputedly said, "Call no man happy until he is dead," by which he meant not that death brings happiness (although that is certainly one interpretation), but that a life can only be judged in its totality, when all the results are in. An otherwise blessed or virtuous life can go seriously sour in its final years, just as an otherwise benighted life can see redemption toward the end. Similarly, moral and aesthetic values may be measurable only over the lifespan of the human species.
At any given point in time, Homer or Shakespeare enjoy fewer readers than, say, John Grisham or Dean Koontz, but in addition to the fact that the former enjoy much more sophisticated literary apologists than the latter, their readership is multiplied over the generations. In terms of sheer cultural influence, readership over time matters more than mass readership within a short period; I can't imagine what the "value multiplier" might be--perhaps 1 million readers spaced out over a century matter far more than 100 million readers concentrated in a year. So while at any given time a taste for Homer would have to be considered a minority or niche interest, in the grand scheme of literary influence it is very much a mainstream taste. Aesthetics is a popularity contest, but those amassing "hits" or publishing figures today are likely the hares who will lose out by far to the turtles in the end.
Similarly, while an avid support for human rights may have been a minority position in Hitler's Germany, in the prevailing context of moral thought, it is now the majority position. There are certain moral convictions--equality for women, gay rights, vegetarianism--that, considered from the point of view of world history, remain very much minority views, but the hope is that over the very long term of centuries of millenia, these will become dominant opinions. When George W. Bush stood by his decision to invade Iraq, he may have been thumbing his nose at contemporary popularity, but he was wagering that in the much larger court of future historical and public opinion, he would be vindicated (we'll see).
As the cliche goes, from the standpoint of science, a tree falling in the forest does make a noise even if no one is there to perceive it. The interesting question is: does a moral conviction hold true even if it doesn't attain its majority? Take the equality of women for example. Many of us adhere to this position even though it has been violated throughout much of history as well as in the world today; but as I said, we hope and intend that in the future of humanity it will become a default moral value. But what if human life had been abruptly ended in, say, the year 1800 by a massive asteroid? Could it be said that the equality of women was somehow a "true" moral value for Homo sapiens even if it had scarcely been observed by the species up until that time?
I think this is true primarily from the point of view of logic. Inasmuch as we are rational creatures, we admire consistency in moral views. So if a premise of one's moral system is that human beings should be treated equally in terms of basic rights, then the equality of women and minorities is logically implied whether or not human beings are around to recognize this. So even if civilization were ended by an asteroid tomorrow (or if Republicans took over the country in perpetuity), gay rights may still be logically valid as an implication of the values reflected by the Constitution. However, this is arguably a formal and somewhat empty triumph. When we press our moral views, we aim not only to persuade our current peers, but also to set precedents that may contribute to crucial influence over time.
So when we argue values, whether moral or aesthetic, the stakes are large--we lobby for the kind of human world we hope to see instantiated in the future. If only a few will join us now, we hold out hope that we may campaign for coming generations. A scientist who feels certain that he has arrived at the empirical truth on a certain matter may be blissful in the knowledge even if it is not much appreciated. But an artist or moralist, while he may tolerate contemporary disdain, must--if he is not solipsistic--be disappointed to know that his vision would be relatively rejected not only now, but also in perpetuity. But I see this, in the best cases, not as an issue of narcissistic admiration, but as one of shared respect for a human ideal. Even those artists closest to schizoid pathology make a bid for connection to future readers. Emily Dickinson did not publish for the most part...but left her poems to be found. Franz Kafka bid his works be burned...but did not burn them himself.