Earlier quoted context omitted.
At best that's a symptom. Cookies are for session management; the central problem with cookies is that people feel that servers will treat certain sessions as ephemeral, but instead those servers track these people for a long-term creepy analysis. One connected problem is that many sites require cookies in order to show public content . Public-content sessions should be entirely ephemeral, meaning that you shouldn't…
For advertisers this is a non-starter, because it prevents you from knowing the size of your audience. All sites would immediately begin requiring some form of "login" in your scenario in order to enable tracking again. If you can't track uniques, you can't sell ads, and that's pretty much all there is to it. So there's huge incentive to undermine any scheme to prevent unique user tracking. The solution is to somehow…
If this is really a non-starter for advertisers, then mandating it will effectively ban advertising, non?
Remember: your business model is not sacrosanct! Disruption!