Notable 'graphs:
It has been said, quite correctly, that whereas the objective of an industry is to generate a product, the object of a business is to produce money. That has certainly proven true in the arts. In music, commercial concerns have been important since the rise of a middle class created an increasing market for songcraft in the 19th century, displacing to the margins the most important former patrons, most notably the wealthy and the churches. Commercial concerns have risen to a peak since the 1970s and '80s, when the world's most important music companies were acquired by large conglomerates, which cemented their transition into being strictly businesses.
This has been quite harmful to the art of music, though it has been a boon for the production of entertainment, as the industry hares after every social trend in the quest to find new ways to pry money out of people's pockets. It is why visual styles are so important in this TV age, and why MTV was inevitable. And it is why music follows and fosters social trends both good and bad, without any evident concern for aesthetics, ethics, taste, or sobriety, and indeed often seems actively hostile toward such things.
As the social wheel spins, so goes music. Trends come and go. Today, emotional intensity appears to be the most important thing, but even so, some waves are receding as audiences show a preference for more positive emotions. Rap, once all but ubiquitous, seems to be waning, slowly but surely; the broader category of hip-hop, though, with its rather more positive social aura, is still going strong.I think that there are some emerging trends along these lines in the Jewish music world as well. The days when anyone with a big enough recording/promotional budget was guaranteed a hit seem to be gone. This past year there were many high-budget releases that simply disappeared. And, people seem to be more open to lesser-known artists then they have in the past.