gidle ive and stayc have proven groups don't need great vocal technique for music to sell.
reversely, nmixx is a group full of excellent vocalists but how are their music doing?
its less about their technique and more about half of their voice tone.
how many seconds do you think yuna and ryujin would get if they were in gidle?
in itzy, they combined for 40% of a song.
in which group do the non-vocalist sing 40%?
i will go out on a limb and say their voice tone (thats 2/5 of the group) and line distribution is what holding back their music and the genres they (the other 3) can do.