Former patent examiner here. The job of a patent examiner can be quite stressful, and I don't think it's particularly amenable to making breakthroughs. At the end of the day I rarely felt like working on personal projects as I was too drained. Einstein and Goto might have had a lot more energy than I do. Alternatively, it could simply be that the huge number of patent examiners (about 10,000 current USPTO patent examiners from what I understand) means that at least a few of them will do something astounding.