The RGN fares were pretty messy... some of the airlines in question didn't take action all that quickly, which likely counted against them. Plus, I believe the "error" was more deeply seated in that case, i.e. a misfiling.
Plus, with RGN you roped in plenty of other carriers who are likely a bit more timid compared to UA, who is on home soil and has significant lobbying power, plus some substantial resistance to any DoT fines that may be charged against them.
I don't know how much "loss" was in the RGN fares that were honoured in the end, let alone how much any fines might have cost the airlines involved, but as it stands there's a significant chunk of fares worth tied up here.
The "paper theory" is that the DoT will "come to the rescue" and the errors must be honoured or UA will face a stiff tranche of fines. The variables are not exactly the same as precedent so one can only sit tight and await the decisions.
Personally I just hope for, at minimum, my money back, i.e. back to where I was before this started. UA credit won't cut it with me.