"the very young are not being exposed to Chess as much as as previous generations and thus we are left with an older generation of standard chess players who are not as willing to adapt to Chess960."
I disagree with this. I think that the majority of chess players are between the ages of 10 and 30. I myself am 17 years old.
I think that the main reason why chess960 is unpopular is because it's a chess variant. It's like trying to make a runescape private server and expecting it to be as popular as the real thing.
If anything, I am surprised that chess960 has as many players as it does. I usually would never expect a variant of a game to attract more than 1% of all players.
Well, I thought I might as well start up a list of reasons why it could be that Chess960 seems to be hovering around the five percent mark of all Chess activities on the internet at best. I'm guessing five percent based on what I have seen personally on the chess servers and general internet news.
Top Reasons why I think Chess960 is at 5% of total Chess activity with no sign of change:
I think the exception is at the elite level where players use Chess960 to freshen their imagination so that when they analyse volumes of standard chess opening theory, they might be more open creatively to novelties. I personally think that explains some of the reason why Nakamura has actually continued to improve as a chess player because he has personally experienced the creativity that is inherent in Chess960.
Other possible reasons I have overlooked: