From a club side where you are trying to promote the sport to a whole range of people, having the solo dance events will help keep skaters in competition whereas they may have left the sport due to a lack of a partner. Those skaters also provide an income stream for the coaches who can still teach them the skills and technique.
You know, a beautiful skater is a beautiful skater, no matter what discipline they are doing. I attended a solo roller competition and there was one girl who just had it. My first thought was she should have been on the ice.
When you have the roller sports who have really developed the solo dance culture compared to the ice side of things, it probably isn't surprising of the number of roller skaters doing solo dance as opposed to ice dance. We still have this thing in ice skating that ice dancing is not dancing unless it is with a partner.