Sam at Bashtarle Symphony talks about idols and talent:
In Japan’s case . . . singers’ lack of natural talent isn’t so much hidden as much as it is ignored.
That’s really it.
A “talent” is not simply an expression of vocal talent, in the way that we often think of it in the West. Rather it stands for the ability to maintain a certain public image, to keep up with a schedule of public appearances, and so forth. The modern era of superproduction and pop packaging leaves true vocal ability almost incidental to the matter.
Related for this, I think, is the modern concept of art. Art is no longer seen as the technical skill of producing faithful replications of visual cues. Instead, it is merely the use of a medium to communicate ideas. What this means is that people who can’t draw or paint to save their lives can still be artists. Similarly, then, why can’t people who can’t really sing be idols?