Google could easily take the initiative on the DNS query front and implement DNSCrypt by default on Chrome. It would booster client privacy and also block ISP from selling usage data. So it would be a win-win for Google.
And Chrome cannot be use dnscrypt by default. It uses UDP ports which are sometimes closed on other networks. So there are technical limitations. Even using another DNS than the network one is often not allowed (you will experience that if you travel often).
Also some people will not like using a Google DNS by default ;)
Also, good VPN services run their own DNS servers, which are reachable only through the VPN tunnel.
See https://dnsleaktest.com/ to determine which DNS server(s) you're using.
Very few people, as a proportion of the population, are paying attention.
Privacy: your ISP has a log of the DNS queries you've made. (of course, they have a log of the IP addresses you've made HTTP/HTTPS requests to, so that may be less relevant).
I'd say most ISPs do it nowadays including some datacentre providers. I only noticed it when my ISP screwed up their DNS proxy making all Cloudflare domains inaccessible no matter which DNS server I point queries to, the packets simply disappear down a black hole.
Good reason to use a VPN, I guess.
After all, it is really a lazy way to save transit costs by making sure that domain names resolve to a CDN they have peered with, or in the worst case, to a transparent HTTP caching proxy they have set up.
Otherwise, it's mostly about how mistyped URLs get handled. Some DNS servers point mistyped URLs to neutral "did you mean?" pages. But others redirect to sites that pay for the service. Even worse, there's the possibility of outright MitM attacks.
And then there's censorship. Hit https://thepiratebay.se/ and see what you get. And that's just a torrent search site. To reach some sites, it takes some work to find a DNS server that will give you the IP address.
I get a database error visiting thepiratebay.se. I can't tell if that means my ISP is doing something naughty, or if it means they're not!
Some DNS servers will show you a page about copyright infringement instead of TPB. Years ago, some German DNS servers were null-routing Nazi stuff. The FBI sometimes takes down sites through DNS spoofing aka cache poisoning. But normally, they go after root nameservers. In 2014, the Turkish government banned Twitter and YouTube through DNS cache poisoning: http://googleonlinesecurity.blogspot.com/2014/03/googles-pub...
Yes, but would it be win-win for us?
Google's already demonstrated that "don't be evil" is now just a sad memory. I'm not ready to believe them to "do the right thing". Their entire existence is predicated on increasing and refining their data collection and analysis, and acting on such.
Google's seedy behavior already directly impacts me every day. I, for one, don't welcome this new corporate overlord.