The nanos will have to drop in price or they will stop selling. Who is going to buy a $450 nano over a $199 480 or a $379 1070? Ive already seen brand new 390s drop to $259 on newegg now and ive been watching the prices of 390s daily since april
The nano is really in a niche market though. It is marketed towards customers that want good graphical performance for their mini-ITX setups (Think HTPC).