The upside of third-party trackers is that you can completely block all of them by just blocking third-party javascript. What are we going to do once all of this tracking code starts getting served from the first party domain instead? Or even served inside the same source files as site code?
I imagine we will start seeing a new class of privacy extensions that behave more like anti-virus. Checking for known hashes of tracking scripts, monitoring for certain patterns of behaviour during execution.
The future is entirely server-side tracking, with no JavaScript executed in the client unless for UX tracking like Hotjar or A/B testing like Target or Optimize.
Personally, I haven't seen a desire in companies to skirt GDPR. Rather companies just want to be compliant and not have to worry about data breaches or reputational damage from their marketing tools. This example with Backblaze is exactly what companies are trying to avoid.
Server side analytics will prove much more powerful and opaque when it gets integrated deep enough into web dev stacks to work properly.