Why should ordinary people or companies be exposed to the full risk of devastating cyclical market mood swings?

Indeed, that is where serious questions must be asked about the true value of the financial services sector, and the wisdom of relying on it for pension funds, corporate finance, etc. vis-a-vis alternatives. There is also the question of the immediate consequences of decoupling by shutting large parts of it down.

With the current system, there's already plenty of pain and misery throughout.

But is it sufficient to catalise major political change? I doubt it. People are far from having lost everything they can, yet. If Russian society under Yeltsin is any indication, it can get a lot worse until someone decides to really put the screws on the financial oligarchs.

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$E(X_t|F_s) = X_s,\quad t > s$