PCs (and, honestly I am really talking about Laptops and the newer PC replacement tablets) are so powerful that they no longer have to be thought of as singular "client" resources. That is, with sufficient memory (let's start at 8GB RAM) and with enough SSD speed storage (>128GB), folk like myself typically run many virtual computers inside our computers.
If I need to run Windows, I just fire up Virtualbox. If I need to do server development, I can pick stuff like Vagrant, Docker or go directly to LXC. I can do Android development. I can do Windows development. I can try out Haiku or some new BSD. I can do all of this without changing the underlying OS. The underlying OS, in fact, is starting to become irrelevant. Give me a Windows box and I can do full Linux stuff on it without replacing the OS: Just start up a Linux VM.
The thing is, at any given moment, my laptop is a Universe of virtual computers. I can network these computers together; I can simulate resources; I can test them, probe them and manipulate them.
This is new. Yes, yes -- the tech is pretty old (e.g. virtual machines), but the realization of this tech on a portable computer is new.
If you want to see where we may be heading, check out something like Rump kernels or OSv. We are starting to leave the OS behind and look at computing in terms of "microservices" -- collaborating virtual computers that solve a particular problem.
With the resources we now have on hand, why are we talking about systemd and Dbus and other single computer entities?
The next time you approach a design, try thinking about how your laptop can be *everything*. And then let that influence your design.