Many ads are brand ads. You don't have to click for the advertiser to get what they want, just see their ad at all. Even for click-based ads, well, most people claim they never click on ads. But, they're wrong. Again, Google has lots of data on this. You will never be allowed to opt out of ads if you aren't paying your way, because lots of people would do it and that would render the internet economically unviable (of course no such ad network would survive for more than 5 minutes).

It was easier to inject a person as a buyer for their own profile into the merchandising system, than to rework all the tracking tools and the analytics that runs on it to stop tracking that specific person.

No, they did it that way because otherwise it'd have reduced publisher earnings who would then have gone to other ad networks with no Contributor programme. How do you set the price of not seeing an ad otherwise? The price of seeing it is set by auction. It had nothing to do with tracking which can be disabled by anyone here:

https://support.google.com/ads/answer/2662922?hl=en-GB

and here

https://tools.google.com/dlpage/gaoptout

Tracking isn't actually the big hammer people imagine it is. That's a fiction invented by journalists. It helps a bit but only really basic stuff like "show German people ads in German" or remarketing (show people ads for products they were looking at buying very recently). That's why it's OK to opt out. You become worth a bit less and you'll see more irritating ads as a result, but very few use this option.

Because I value privacy as a principle more than a slightly less useful product, and I would pay for it. But apparently I can't afford it.

Go disable ad tracking then. The options have been there for many years.