ISPs are more likely to move in the direction of reading your traffic to inject ads rather than remove it.

Maybe - But that choice is taken away from me completely.

It's not. You could install a root certificate from the ISP and then they could man-in-the-middle your traffic.

Encryption is what allows user choice rather than leaving you at the mercy of your ISP.

Its not true. At least in mobile app they use something called ssl pinning to serve ads.

Then your problem is that you have a locked down device that isn't truly yours. App makers always had the ability to use a proprietary encrypted protocol to serve ads. DNS-over-HTTPS doesn't give them that ability. But it does provide a standard that people who do really own their own devices can use to preserve user choice. No one should protest that.

You can't easily use custom root certificates on Android.

If both of the two ISPs that serve my area make the choice to inject ads for me, that choice will be taken away from me completely.

I'd much rather take away the choice to screw with what I see from my ISP.

Why not just run pi-hole?

I don't think that will work with DNS-over-QUIC in the browser, but I could be wrong.

It will if your device speaks QUIC; you can configure your browser to talk to that device.

But I do think it makes much more sense to make the browser just do the job directly, rather than delegating that to a separate device.

Firefox continues to block ads just fine, and it'll keep doing so in a QUIC world, while protecting me even more from malicious local DNS servers. The average person is much more likely to encounter a hostile DNS server than a "helpful" one.

You mean like the customer loyalty card at your supermarket? That's all about making your life better, right?

Google only ever shows you ads you want, never "unwanted content". Are you suggesting Google could do even better if they just knew a little more about you?

I'm not sure what exactly you think I'm saying. My point was that this is a feature I would pay someone to provide me. Like adding: "Ad-Removal-Package - 5USD$" as an optional add-on.

I'm not saying I'll be giving them unfettered access to my browsing habits so that they can give me some perceived monetary benefit in return. But even if that were the case, so long as they didn't do anything fraudulent or violate my privacy by giving my personal data out, then I'm 100% fine with it. This is no different than Google having algorithmic access to all my personal emails. Once we figure out the two scenarios are the same, we'll quickly realize this whole "protect me from my ISP", "privacy" movement is just a front for taking away people's right to control their own hardware.