Also ads get people a continuous income on their blogs. But then I think the whole idea of decentralized social network also includes to keep it ad free and free from customer targeting. However, the ad free system comes with a drawback where content creators only get paid for 7 days, even if the content is useful to public in long run. I think there is however a possible way out it. An alternate platform, something like WordPress which automatically publishes articles from steemit, after it is more than 7 days old. So while steemit system stays ad free, the content creators can keep benefitting from their content by letting advertisers promote their products through these blogs. So while steemit rewards and selects quality articles in first 7 days the selected articles can live their life forever on the alternate platform. Though I am not sure how feasible this would be policy wise, I think it is something that would be nice.