That's a nice rationalization of the situation, but history shows that being smart enough to do one thing has almost no correlation with being smart enough to do any other specific thing that wasn't already necessary to do the first. I doubt the ability to implement blockchains has anything to do with such socio-political analysis, and so should you.

I would say expertise in cryptography correlates with expertise in keeping your information private, no?

Expertise yes, but not necessarily desire to keep your information private. There are many expert cryptographers who are much more public than Satoshi.

It wasn't a question of motive, but of skill.

That's a good way of putting it. Many other people in a similar position may have chosen to be public. Many other people would have chosen to remain private but failed at. It takes skill to chose to remain private about something like this in a way the remains (at least so far) resistant to at least som concerted skilled effort to find you.