...in the end, given time the prequels will gain popularity. There's one element that is missing in regard to the prequels. Nostalgia. My son loves the prequels. He has no preconceived ideas of the events surrounding the prequels... unlike my generation of fans. And when he gets to be of an age where he too will have some disposable income, the vote he casts with his dollars will tilt the scales in the prequels favor.
Nostalgia... it has elevated movies such as Clash of the Titans, Tron and Goonies... films that were slammed by sci-fi fantasy geeks when they first were relased. Even Jedi and the whole Ewok population has been elevated in this way. We have already seen an increase interest in Qui-Gon as a character... and it's only been 7 years.