First, I think there's a lot of truth to the idea that NSA's primary motivation is headcount. I think that's an important and significant point that isn't raised often enough in these discussions. It has implications beyond vulnerability disclosure! (For instance: it's a very good reason to be wary of things like DNSSEC, that make it expensive but not intractable to attack Internet trust at its core).

But I don't know what you mean by your first paragraph, or by the notion that "cracking systems isn't going to lead to anything worthwhile".