For all that was good about it, I blame the 60's for this one. Let's face it, even with the new options available, partner dance is kind of like traditional marriage. One man, one woman, the man nominally in charge. Very old-fashioned. Not something appealing to the baby boomers in general. They were still partner dancing in the 50's. Ballroom dancing lost a generation, and that generation did not transmit an appreciation for partner dancing to their children.