Docker's next move distills all those pieces into a single product: Toolbox.
Toolbox is not actually a solitary, Docker-branded product replacement for the separate pieces. Rather, it provides a simplified way to obtain, install, and organize them without requiring the user to ferret them out individually.
According to Docker, Toolbox will not only help prospective Docker developers get up and running, but will also allow people to work on a desktop development environment with apps already defined in Compose.
One feature of Toolbox: It partly subsumes Boot2Docker. Originally, the Docker VM was managed by the boot2docker command-line tool (supplied with the Boot2Docker image), but now it's managed directly by Machine. The VirtualBox virtual-machine application is still used to launch the Boot2Docker distribution.
For those who depend on the Boot2Docker stack, Docker has made accommodations. Existing Boot2Docker installations are automatically migrated over to the new tool set in Toolbox, for instance, as shown above.
Kitematic, formerly an independent outfit, provided an open source GUI for Docker that boots a minimal Linux image inside VirtualBox. That product hasn't changed a great deal since Docker acquired the company, minimizing disruptions for workflows already built on top of it.
Docker could likely consolidate more of Toolbox around and underneath Kitematic -- and make Toolbox a one-stop, GUI-driven avenue to Docker on the desktop. There's room to add other tools from the Docker landscape -- such as Docker Compose UI, an in-the-works graphical interface for Compose.