Scirra has expanded in the near past (they hired a developer), and based on Ashley's posts they plan to expand again. But it's their business how they manage the company.
By the way: IMHO, multi platform support for the editor is not needed. If I want to run it on the Mac or Linux, I can use Virtual Box with Windows for it. Also multi Language support is not needed - not for the editor. People who are not (enough) speaking English, are mostly Kids. The problem is: they usually have no own money.
I see your point, but I think many of the users would not agree with this. IMHO if cross-platform can be supported by designing the new editor towards that from the beginning, it's a good selling point and a welcomed feature by most of the users. Remember, not all C2 developers can run a virtual machine or have stong enough computers to do so.