I'm all for news sites, for example, hoisting ads if I knew they were getting the money from those ads, knew the ads were actually coming from their site.
I wonder if you could hijack those requests at your router and send them back to your Pi-Hole? But then they just switch to DNS over TLS...
In the corporate world, I think the future is managing your network by managing every single device on your network. Only let authorized/corp devices in and all those devices must be enrolled in an MDM solution that enforces all sorts of policy and includes monitoring traffic/DNS queries. Of course that's a lot more work than just monitoring things at the network level.
Your computer sends the raw domain name to pi-hole (e.g. ads.google.com), and pi-hole returns 0.0.0.0 if it's on the block list.
There's nothing Google or anyone can do to make pi-hole stop working.
For now, I've configured my router to force all UDP port 53 traffic to my Pi-Hole which overrides what I mentioned above.
But, in the future we may start to see IoT Devices hard-code DoH servers which will be harder to force over to the Pi-Hole.