KOL are now considered mainstream because they now make mainstream music. Moffo - don't pretend that if they had released Youth now that they would be just as huge as they have become - commercial radio wouldn't touch it.
The difference between a Nick Cave and a KOL is that Nick Cave wrote an album not giving a rats whether singles get picked up by commercial radio or not. KOL clearly did.
As for the Top 20 published now being mainstream...they weren't mainstream when they were first released in a number of cases...amazing how quick commercial radio picks up music once stations like JJJ, 4ZZZ, 3RRR, FBi, et al create an audience for it. Rightly or wrongly, where would acts like The Presets and Cut Copy be without JJJ?
And lastly...Simmo - that came straight from the JJJ website and I didn't think I needed to proof read...obviously I did