This concern started being addressed in the latest DoH draft.

I know people are working on encrypted SNI but that will take time.

Assume a large entity willing to do some mass surveillance (NSA, ...). Now with unencrypted DNS this entity just has to MITM a link on the last hop of a few DNS providers (Google, Cloudflare) and voila, the IP's of the clients and the domains visited are pouring in.

With encrypted DNS, for an entity to get the same amount of information they need to MITM a much larger amount of links.

Though I agree the benefits are clearly limited, the idea is to eliminate all weak links. If there are 2 broken windows in your house and you can fix one - why not do it?

In terms of privacy, I would mostly agree. Using an authenticated channel to your resolver still protects against many common MitM vectors, so there's definitely a benefit there. Unlike DNSSEC, you're not dependent on the target domain being in the small subset of DNSSEC-enabled domains, not to mention that most client resolvers won't validate DNSSEC anyway.

If you're that concerned about privacy, you better use a VPN.

CDNs have been doing, and keep doing a great job at pushing new things forward.

Fastly, Cloudflare and Akamai already have implementations and test websites.

I have no clue how often this attack vector has been used in the real world, but last time I read about it, I got the impression that it would not be very hard for a skilled attacker to pull off. (DNSSEC would work, too, but as you say, most clients do not make use of it.)