As we all well know one analysis of the Great Crash is that it all happened because financial markets werte too concentrated. There were banks that were "too big to fail" and which we couldn't just let go bust therefore we had to bail them out. I certainly ascribe to part of that analysis, or to it in part perhaps. And a useful solution would therefore be to break up large banks so that none are in fact to big to fail. Seems a logical answer.