Satoshi did mine Bitcoin however. And from what people estimate he might own over a million coins from doing so. However its hard to say if he mined for money or not since people don't know if he actually spent any of it.
One of the reasons why he kept mining it might of been to keep the chain going, without someone mining the chain would come to a halt and people wouldn't be able to make transactions.
He stopped mining when more miners started to enter the market because he didn't have to mine then to keep the chain going. Whether he sold anything or not is hard to detect. Since nobody knows exactly when he stopped mining. He might be alive and well and selling his mined coins backwards, like from 2010 and on to prevent detection.
That make sense. Thinking about it, mining few honderd BTC a week with a home computer