DNSCrypt and other solutions typically involve changes to the DNS resolver in the underlying operating system. That's a lot harder to get changed and deployment can take a long time.

DOH can be implemented directly inside of the web browser application, since those browsers are obviously already doing everything over HTTPS. So the browser developers just have to build in a DNS client. From their perspective, I would see that being much simpler. And deployment is as easy as the next browser application update.