The problem with this theory -- the "holds a position too important a role in the popular perception of the institutional infrastructure to hold accountable for personal misdeeds" theory, which, aside from the financial collapse was frequently cited to justify the Ford pardon of Nixon -- is that:
1) As soon as such a principle is seen to be operating, it licenses further and greater misdeeds from those in the positions to which it applies, and
2) It ignores the damage (which may be less severe in the short-term, but is likely to be more lasting in the long-term) to public perceptions and confidence that the lack of accountability itself produces, including that resulting from the inevitably common perception (whether or not its accurate) that "too important to charge" isn't really about protecting the public from public harms resulting from damage to confidence in the institutional system, but is merely one of a set of a self-serving excuses that elites use to protect other elites from accountability to the superficially generally-applicable rules of society that are the only thing that protects everyone else from abuse by the elites.
This isn't an individual case like Nixon but rather an industry-wide epidemic of sorts that would have pushed the very inter-dependent markets into chaos.
None of the bank executives at fault were that important to consider not prosecuting. However their institutions and respective influence on the global markets were (in their options) that important to maintaining stability (albeit a false one) that was deemed the lesser of two evils.
> This isn't an individual case like Nixon but rather an industry-wide epidemic of sorts that would have pushed the very inter-dependent markets into chaos.
And in the Nixon case, it wasn't a case of leaders of private institutions, but the President of the United States at a time of deep national division even aside from the proximate issues with which he might have been charged, and it was perceived that charging would have thrown the whole nation into chaos (and not merely financial chaos, but actual fighting-in-the-streets chaos.)
There's always a reason why accountability for elites in powerful positions is a special case that can be asserted to be sui generis and requiring special exceptiosn to the normal rules of accountability. But the impact of accepting the temptation to do this is that it rapidly becomes clear that elites are not accountable in general, leading to more elite abuses and less long-term faith and confidence in the very systems that the exceptions are intended to protect (short-term) faith and confidence in.
To avoid the long-term erosion and destruction of this faith and confidence, you have to accept (publicly) that the system at issue has been broken when it has and hold people accountable, even though there are severe short-term consequences. Otherwise, the long-term consequences are more severe.
Or, as a much better writer than I put it -- "The tree of liberty must be refreshed from time to time with the blood of patriots and tyrants" -- you cannot save the integrity of the system if you are overly obsessed with preserving the myth of the existing integrity of the system.
1) As soon as such a principle is seen to be operating, it licenses further and greater misdeeds from those in the positions to which it applies, and
2) It ignores the damage (which may be less severe in the short-term, but is likely to be more lasting in the long-term) to public perceptions and confidence that the lack of accountability itself produces, including that resulting from the inevitably common perception (whether or not its accurate) that "too important to charge" isn't really about protecting the public from public harms resulting from damage to confidence in the institutional system, but is merely one of a set of a self-serving excuses that elites use to protect other elites from accountability to the superficially generally-applicable rules of society that are the only thing that protects everyone else from abuse by the elites.