Even the most noble of the sacrifices is based on "self satisfaction". Jesus Christ himself was crucified for the sake of his people for "self satisfaction". That's why you shouldn't expect anything in return when you help someone. Because the moment you expect something, your act would become worthless.
It doesn't matter what you achieve in life. It's how you live that really matters. Countless men have lost their lives in war without fulfilling their life's ambitions. Shiba stood by his convictions, no matter how lonely he got. So I think that in the end, he must've been happier than anyone.