You're citing adsense which is CPC while most media is CPM and display advertising. They are two entirely different sectors.
AdSense struggles to distinguish between DrDobbs and a 12 year old writing about learning programming on Blogger. It performs when you have purchasing intent based sectors like gadgets, photogaphy, etc. (and a lot of blogs have built around that)
There is also a confusion here where CPM is used to refer to total CPC revenue divided by total pageviews. CPM is a specific display model where advertisers purchase Units of traffic volume and it scales out.
In any case neither DrDobbs nor GigaOM ran CPC ads in any significant volume (likely would only fill unsold display as backfill).
It is telling that somebody from DrDobbs - a display ad business would cite AdSense CPC performance or ad market performance as a reasoning for their failure. To me it just speaks to not understanding what went wrong.
Nobody should expect to take a premium magazine like DrDobbs, split it into online articles and then slap AdSense onto it and then sit back and count the money. That is totally unrealistic. It also doesn't work with just CPM markets either.
Premium brands require humans to sell them and not algorithms. If you don't have the scale to hire a sales team then you need to join a network.