Satoshi went most of his BTC history not knowing if GPU mining would ever be. And not he never implemented his ideas of which there were many that counted on no GPU mining.
Satoshi knew pool mining was coming just like he knew gpu mining was coming. Back when I was mining with my laptop, the tiny bitcoin mining world was about to shrink to include only those willing to buy gpu's. Satoshi saw that as bad because it would mean that it would take longer for a large number of people to obtain bitcoin. There was a gentlemen's agreement to delay gpu mining.
I think coming up with a way to break blocks up so that 250 computers could mine 1/250th of a block while maintaining hash power in the network would help solve the pooling/central hashing issues.
Following Dr. Goss is one of the fastest ways noobs in BTC historically can lose coins.
Satoshi knew that GPU mining was coming before anyone even thought about possibly GPU mining. When someone suggested using GPUs to mine more efficiently he asked people not start this yet because it would prevent additional users to "invest" modest CPU power to try mining on their own (so the network could become more decentralized).
satoshi did have a lot of hashpower (as a percentage of the total network) so it is possible that he himself was using GPUs to mine at first