That way you can get the benefits of a network + the benefits of serving from the same server that is serving the content
It would come at the massive expense of high-quality tracking and thus incur a massive reduction in ad revenue, but it's an imminent trade-off that beats unconditional adblocking.
I think everything is just waiting for the actual tipping point that forces everyone's hand like we always do. Adblockers are still the minority.
For example, the ease of Adsense is the only reason why my forum is still alive. It's a medium-sized collaborative fiction writing forum with a userbase composed of mostly teens without money (I've tried scavenging for donations once).
Every year my banner ad makes me less and less money. And when it stops breaking even with its rent, I will close it down.
Now, some people in these threads, even perhaps yourself, would argue that my forum simply shouldn't exist since it's dependent on ads or because "I'm too lazy" to spend time trying to find a business model for a forum that already makes me almost no money, but it would be a loss for my users.
Meanwhile, hosting your own ads entails finding advertisers, wooing them, developing a relationship with them, maintaining that relationship, negotiating a contract, settling that contract, building an ad-serving system somehow, automating it somehow, etc. And that's if you're even big enough to attract anyone or even warrant the work to begin with. And the second you try to generalize it (which is what ad networks do), then you're back on every adblocker's default blocklist.