Owning or not the content?

So in a discussion i had at the Borrell Local Conference in NY, the subject of shall we as media companies try to be aggregators of audience, no matter where it comes from, or shall we attract more audiences because we own and control the quality of all the content we display , is the way to go?
I believe that marketing is about engagement, advertisers pay to be associated with brands, with othher products rather than just place their ads in front of the consumer. Why if not they will pay for advertisement in the digital world? Instead they could just create their own content and buy traffic to tho sites, no more media to come to for advertisement.
W will have in such world a consumer package goods company also becoming a media company. RedBull is trying to get there, prints more than a million copies of their magazine in Europe! But they keep looking for brands to associate their product… Why?
Simple, i believe that media profesionals have the key to “engage” the consumer with good, curated media.
Other than doing that, there is no reason for us to exist and we become another ad network.