Actually, the source is hosted at git://git.macruby.org/macruby which is owned by Apple.

So yes, unless you provide the evidence to support your claims, I'll assume that all MacRuby work is being done in public on macruby.org, similar to how other Apple open-source project work (llvm, WebKit, clang) and that the amount of that work is representative of Apple's commitment to the project.

In comparison, if you do similar stats on other Apple projects (like llvm, WebKit) you'll see that they have order of magnitude more people working on them, producing order of magnitude more code.