The problem with server side ad insertion as you call it is the lack of accountability.
It gives way too much power to the publisher: they want the ad money and therefore have all the incentives to commit fraud.
At the moment, having the ad distributed by a third party and a ton of other third party JS in the browser allow all parties involved to cross check each other.
The bot problem would be way worse with server side.
It gives way too much power to the publisher: they want the ad money and therefore have all the incentives to commit fraud.
At the moment, having the ad distributed by a third party and a ton of other third party JS in the browser allow all parties involved to cross check each other.
The bot problem would be way worse with server side.