At this point there is no precedent in US capital market history for the government to "declare" a set of equity preferreds as "having no value" when the companies are spinning off massive amounts of profit. (If someone can find a precedent, am all ears.)
Doesn't mean it can't happen as a "first" but the odds are now low, and will be lower still as time passes.
And it is VERY interesting that Treasury has been VERY careful never to impugn the jr preferreds.
I do think the risk is an extended timeline, perhaps longer than some investors contemplate.