Last year I got downgraded F->Y twice on just one segment of a two-segment itinerary (once due to idb during irrops, once due to equipment swap). In both cases I was immediately offered compensation as well as fare difference when I called in, although the agent had to call accounting to do fare difference. Maybe your definition of "stalls" is different than mine.

Keep in mind though, that during both these episodes, I was 2P, so was dealing with ICC.
Of course, that is not to say that everything went smoothly. My main complaint is that my refund was calculated as what I paid (A at the time of booking in both cases) vs. lowest econ fare at the time of downgrade (presumably the day of the flight; in one case, it was Y), when reason would dictate that it should be based on the lowest economy fare that was available when I originally booked my ticket. I mean, c'mon, we all know Y>A in price sometimes! It took some haranguing to get a more appropriate fare difference (made all the more annoying by not being able to talk directly to accounting - have to go through the CSR as a middle man) but at least it was accomplished during the initial call.
In my IDB situation, I didn't want to have to deal with accounting again so pushed for more compensation, telling the CSR it was a customer service issue. The increase in compensation on their second offer, if applied to the fare difference, brought it sufficiently in the right ballpark that I just accepted it without pushing the fare difference issue further. For faster resolution, I would recommend going this route.
I suppose the mere fact that we've had such differing experiences is a problem in itself (I'll also presume your status was higher). Anytime someone is downgraded F->Y, there should be at minimum an immediate fare difference refund, and UA needs a new official policy that better reflects the actual difference in fares (i.e., what was paid vs. lowest econ fare at the time of booking)... especially since we'll see more "dying TED" swap-ins on non-TED routes through the end of the year.