as time shows, there really isn't a bubble when it comes to high grade mantle cards.
simple supply and demand in which only mother nature will decide when the mantle/mankind bubble bursts.
edit: i was in on the action, however was outbid and really didn't mind...as i picked up something else very special and will be more than happy to display once she arrives! ; )
but here's my auto'd version and my 5 which did not get upgraded (only by psa's opinion):