Do you really need stats that an A.D.A. gig is easier to land than biglaw???
From my anecdotal experience, in every town I've lived in the D.A. and public defender offices tend to be populated by people who went to fourth tier law schools or graduated bottom of the class from University of Insert State Here. Also, biglaw tends to hire in fall of 2L year and you get your offer in fall of 3L year, so people who are left in the job applicant pool post-graduation tend to be people who didn't get biglaw or midlaw or small law with SA programs.
The only hitch is that you usually need to be admitted to the bar in the state you're applying. It is hard to get FIRM jobs in less urban areas if you have no compelling reason for explaining why you want to be there, primarily because of the summer associate process because nobody wants to waste $30k on a kid who is going to leave. (Also, because firms generally over-pay you for the first few years and then expect a return later.) The government is usually cool with the fact that your compelling reason to be there is to get a job. Also, I'm sure there's some cronyism going on in lots of small towns for those kinds of gigs.
If you want to serve people, that's great. If you want to work in government, that's great. If crimlaw is your thing, that's great. But highly selective? With the notable exceptions of a few major urban areas, not really.
::shrug::
My only experience is in a major urban area, and, anecdotally, those jobs,
in this region, seem to be harder to get than BigLaw gigs, in some respects (as in, they might not care as much about grades, but they definitely care about whether or not you can convince them that your interest is genuine). I'm sure you're right as a general rule, though.