I think part of the problem is that developers are expecting business people to have the same set of values and to really care about the answer to "should we unit test or not?". We don't get approval beforehand from the business to use a high-level language rather than assembly language -- it's just usually the sensible way to get the work done.
The point is, we are the only ones qualified to make the call (which isn't to say that all of us have the same knowledge on the topic). Furthermore, even if your team doesn't, as a matter of policy, do unit testing (or name-your-method-of-the-day) it generally doesn't mean that you can't do it.
The truth is, we can't really prove ROI on most of the stuff we do at too fine of a granularity. Why unit testing is held up to this unreasonable/non-typical standard of proof is beyond me...
