The aforementioned companies make more than web browsers. They make entire operating systems. If an OS changes how it interfaces with DNS, it will affect every

The aforementioned companies make more than web browsers. They make entire operating systems. If an OS changes how it interfaces with DNS, it will affect every service that runs on the OS. To be honest I don't see this happening any time soon with the major commercial OSes. But in Linux you can install some programs to e.g. send all your DNS queries through a certain encrypted tunnel, and nearly every application installed on that box will happily use that tunnel.