> Now, Google does claim they don't track DNS requests. But consider why that is? Once upon a time they didn't scan Gmail content either, but that was before GMail dominated the webmail space.
You seem to assume that it's a singular organization with a unified agenda, but this really isn't the case. It's the same thing about when folks assume Google looks at your Drive files to recommend ads to you -- it isn't true, there's different motives there.
Drive: we want to sell you storage, your data isn't scanned (except for viruses). Google DNS: speed up DNS, which improves load times, which improves the overall web experience. Photos: Ditto, we want to sell you storage.
Performance is a feature, and most ISP resolvers are junk. Worse, many of those resolvers like to inject their own NXDOMAIN pages. :\
You could argue that Google DNS does positively impact Ads, but only in the respect that faster DNS resolution helps ads load faster too. Overall, I see it as one of those "long term greedy" (my own words) strategies.
As a privacy-conscious Googler myself, I've taken a look at Google DNS to convince myself that it's what it says on the tin. As far as I can tell it is, but I don't expect you to take my word for it. What logging exists is extremely temporary (short-term debugging.)
Re: Gmail, this isn't true either. Sure, there's still processing of your emails (we receive your email, scan it for spam), but it isn't used for Gmail ads. The public perception of this was so bad and the incremental improvement in ad quality so low, that now ads just use your general ad profile. No email scanning involved.
> Software stacks, configuration policies, etc will have all evolved to disfavor niche use cases and favor Google, Cloudflare, etc.
This is a different matter entirely, but this isn't _always_ a bad thing. I'm thinking of TCP here, which has almost entirely been ossified by middleboxes. Same for TLS -- TLS development has been hamstrung by these same kinds of middleboxes and "protocol accelerators." This kind of incredible technology position has allowed for the acceleration of HTTP/2 and the development of QUIC (and therefore HTTP/3). Overall, Google has been incredibly open with the development of these and worked to include everyone. I'm sure it's not always that way. Can you bring up some examples where "niche use-cases" have been locked out by Google-driven software stacks and configuration policies?