A theory, other than the fact that the youth of today have the attention span of goldfishi. Snooker was in the doldrums from the mid 90's to 2009. In that time, the sport had less appeal than ever before. Therefore, less people took up the game of snooker, making it less likely that we would have great players. Whereas during the glory days of the 80's, people like ROS, John Higgins, Mark Williams, Peter Ebdon, Doherty, Hunter grew up watching and were drawn to the game.
Could be a bullocks theory. I hope it is, because that could mean we'll be another dozen years without a great batch of young snooker players!