I don't understand how you came to the conclusion that a dancer "can't progress" because single dance events are not always offered in all dances. Even if you start in Novice you don't get all the dances: generally, Novice is a three-dance event, Pre-Championship is 4-dance, and Championship is all 5 dances.
The point system wasn't set up to prevent people from moving forward before they were ready -- there are no minimums that you have to earn before you are "allowed" to move on. Rather, the point system is set up to force people who have achieved success to get up out of the lower levels. So, you can dance Gold Syllabus even if you've never eared points in Bronze in Silver, or if you've only earned points in a few dances. (Ditto for the out-of-syllabus levels.)
If you've been studying syllabus for the past 2.5 years it is most certainly not a waste of time. However, it would be a more effective use of your time to see what dances are usually offered on your syllabus level and concentrate on those. For example, if none of the comps you're going to be in offer Paso Doble at the Silver level, then focus your energies on the other dances and leave off the Paso until later. That's the whole point of them not making you do all the dances at each level: to give developing dancers a "smaller bite" to chew on while they prepare and progress.
