Earlier quoted context omitted.
Netflow data, DNS capture, enrichment of cell tower access data (location), reporting on non-usage (idle time, tracking), Bill and household information, credit account usage, etc. SPs are huge sellers in this market. We still need to encrypt the accessed resource and DNS queries everywhere. Even once that’s done, things like opencaching will be used by SPs to gather tons of data where they participate.
What about 8.8.8.8? I'm guessing we're just trusting Google here (and Cloudflare 1.1.1.1 who now also does 10gb free VPNs) + the good will of engineers with access to this information within Google.
But the limits of using google DNS (or even encrypted DNS) is that most commercial websites aren’t sharing IP addresses, so I bet the ISP can pretty much reconstruct the data it would get from DNS with very little effort just by looking at your IP traffic and mapping IP addresses to domains from other users DNS queries.