Even if they made $0.00 from ad revenue, they would still be on the losing side of the battle against tracking. You can't have many features without exposing something about the client. As soon as you have things like multiple versions, optional features, plugins, and UI metrics, you've lost the battle already. Just your fonts alone can identify you to a reasonable accuracy.
How would you solve this problem? Have everyone run the exact same browser in a virtual machine sandbox, with all traffic running through a common VPN? No plugins, ever? No i18n? No preferences of any type? Upscale a fixed-sized image to your screen's physical resolution and just learn to live with the blur?
That's where you'd have to begin, but I guarantee the ad people would find a way around it. Key press cadence timing. Mouse movement patterns. Something. They'll find a way.