Why can't the site just collect some data from the client and forward it to the ad networks on the backend? All of this stuff needs to happen out of band.
Everybody is cooking their own soup and no-one wants to share their toys and sandbox with the other children.
Sharpers and snake oil salesmen peddling nonsenseware to terrified publishers who watched their entire business model crumble to sand in the face of craigslist.
Good question: we are getting there with the major DMPs (data management platforms) which are Krux, Exelate/Nielsen, BlueKai/Oracle, Adobe, Facebook and Google. There are dozens of smaller players but they now all hook into these major 6 so those are the tags you're seeing.
At this level, these are billion dollar companies so there won't be much more consolidation.
Because the trend is for the client to bear the burden.
It sounds like the Mozilla solution of building some kind of intelligence around advertising might be the way to go then. Injecting all this stuff in the page load is crazy.
Because the ad networks don't completely trust the publishers.