I agree with you. Linux is possibly a bad example, there's nothing special about writing it.
Are you sure about it? Wasn't it one of the first really large software projects with the distributed development model? (Were there any predecessors to that?)
By the time Linux was born, the GNU project had produced a large collection of tools, enough to have its founder claim that the last major missing piece for it to be a complete OS was a kernel.
Well, yes, but the individual GNU tools are to a large degree independent. I'm not an insider, but to me it seemed that the kernel development effort really pushed the limits in the area of distributed development of a single large code base. (I'm not sure, though, how exactly did the kernel code base measure with the contemporary GCC code base, which is probably the closest in complexity from all the GNU stuff.)
