Which is to say iterated waterfall with stand-up meetings tacked on.

You're not doing it right :)

I kid because I love, but I will say it depends on where you're attempting to do it, how much control you have over the process, whether you are a contractor or government employee, and how much your can convince your leadership of the good parts (these typically require actual risk-taking / change)

It can be done. Not for everything. But for a lot of things.

Disclosure: I work for Pivotal. Through Pivotal Labs we have various consulting engagements with the US government, including the DoD.