I'm not sure that all the examples you cite are evidence of very successful and profitable media companies. ReadWriteWeb was acquired by SAY Media for less than $5M and they cut it loose two years later. HuffPo wasn't turning a profit for AOL in 2013, and Tim Armstrong wouldn't say in Dec. 2014 if it was earning a profit, which basically means it's not. In any case, HuffPo's revenue is largely driven by rehashing the original reporting of other outlets, and that is definitely not sustainable journalism.

[0]http://techcrunch.com/2014/11/13/say-media-selling-off-readw... [1]http://www.businessinsider.com/aol-huffington-post-profit-20... [2]http://www.businessinsider.com/huffington-post-over-200m-rev...