If that is the case, we wouldn't have been contests and promotions where people ways to generate content. We would be having, but the intensity would have been significantly lesser. Whether you are writing as a personal blogger or for money, passion is always there. In such line of work/hobby, you need passion to drive new content and have a steady growth of quality along with the readerbase.
But, eventually, when a blog grows to a point where it demands your full attention, you would expect that it should earn some money from it. If you look at guys brown paper bag, its the same deal. Medianama has published an article on them which shows how their business model is, which is great considering their source of money is beyond advertisement, which is not really an easy thing. But fields like tech blogging, assuming one is very serious and invests a lot of time on it, they can earn only from their pageviews count and referral sales, and if they're decently influential in real world and have a very engaged userbase and forums, they get pretty decent amount provided you dont destroy your credibility- which doesn't take much effort at all. You're practically running your own publication. For such people, the more influential you are and more 'powerful' you are in regards to readerbase activity, one cannot be messed with unless they choose to comprimise.