We (the systemd developers) want systemd to provide the basic building blocks from which you can build an operating system. Networking is definitely one of thes

We (the systemd developers) want systemd to provide the basic building blocks from which you can build an operating system. Networking is definitely one of these, so we want to include it by default. However, you are of course free to use an alternative network management solution, and at least in the beginning we expect most people to stick with what they have. Distributions could easily ship networkd as a separate package, if they so chose.