If Satoshi would have  wanted to use his bitcoins he would have done so when the cost of bitcoin reached $1200... nevertheless it would have risked his anonymity, also t is based under the assumption that he has 1.5 million bitcoins... what's he gonna do with them if not spend them or utilize them.. keep them as a souvenir... I hardly think so...
Anyways... Human mind is a complex structure and a mind of a person as smart as Satoshi... maybe he has found out a way to do something with all his bitcoins by not doing anything with them...
MIND=BLOWN