When there is marked discontinuity with the past, such changes may be far-reaching and the past fails to provide enough guidance for the present (never mind the future). We should always remember that the financial system is part of a richer social, economic and political environment.
The real world is subject to shocks that at times may have dramatic consequences, such as those that we have experienced in the last twenty years or so, with the end of the cold war, globalization and the sudden emergence of new major economic actors, the ICT revolution, and substantial (not completely anticipated) demographic changes.