That, or they already leveled their AST to 60 and are now leveling other classes so you don't see them as much in leveling dungeons. Or not many of them in hm trials since majority of folks who run them seem to be light farming and, well, no relic for AST. I just light farmed my SCH relic and about 10% of my co-healers were AST. Neither of those suggest the lack of AST majors, just that the initial influx of people who level it is over since they are max level.