I think a thing with some of the powerhouse (not all) is that they tend to be live performers more than anything. For example: Kyla, Rose, Desz, and Dana all have less than 5 original songs each on their spotify pages. Also, since people love them for their larger-than-life voices, they usually sound better singing live on stages than in the studio.
Compare that to some of the other contestants. Chevel, Sid, Zan, Taryn, Danielle, Addison, and Brynn all have a bunch of singles and albums/EPs out.
Not saying that this is the sole reason, because there are plenty other popular contestants who are also sparse in their music releases and have long fan threads. Just giving a piece of my insight.