Chainalysis does it all the time.

Satoshi left the scene without ever cashing anything out, and before blockchain analysis really became a thing. He's not relevant to modern bitcoin at all outside of having been a founder of it a long time ago.

If he were spending bitcoin today, he could be found and identified easily, which is likely why he (actually the conglomerate that posed as him, Satoshi isn't likely a person) left once he achieved his goals.