This is fairly naive and also misses the fact that corporations have been around for a very long time too and don't have a great moral track record either. The Dutch East India Company at its peak dwarfed any modern corporation in terms of wealth and power[1] and was incredibly exploitative and corrupt. The British East India Company caused Opium addiction in China and kickstarted the colonisation of India. Industrial capitalists created (and still create) inhumane working conditions for their workers. If you count the whole sum of human misery created by the economic demands of the slave trade it becomes harder to even confidently assert that governments or religions have caused more evil.
This is not necessarily to say that corporations have caused more evil than governments or politics, but they do have a long track record of evil too and shouldn't be given "the benefit of the doubt" any more than any other organisation with a large amount of power.
[1] http://www.visualcapitalist.com/most-valuable-companies-all-...
I'm not convinced that we can't have the former without the latter. But that would mean limiting the latter and there is not much political will to do so.
Implicit in this question is the idea that the destabilizing effects are actually a large amount of the banking activity. I would argue they are not, we just hear about that far more often because it's bad news, and bad news is more interesting. The rote, mundane functionality of all banks, including the big ones, is mostly under the radar and (in my opinion) vastly underappreciated with respect to banks' occasional tendency to throw the system out of whack. In particular, I would posit that the latter is more a manifestation of common economic activity than it is to a centralized and consolidated banking infrastructure. Or, more succinctly, that economic activity at the modern scale does not sustain itself without these banks working more or less as they do now.
There are certainly improvements to be made, for sure. But I personally discount the possibility that those improvements would radically reshape banking infrastructure or significantly reduce the volatility cycle we encounter every decade or two.
Corporations and the ultra rich are pretty new arrivals in the picture and I am willing to give them the benefit of the doubt. Especially since their track of record during the last century is net positive (much more good things coming out of them than bad).
And especially considering the βnewβ way they made their money, through adding value instead of the old way through being born into is, stealing and pillaging...