Keynesian / Free-Market Debate

The Keynesian vs Free Market debate has been a cause for contention and fiercely contested throughout recent history of economic thought, with strong arguments being put forward for either argument. Proponents of the free-market ideology, such as the acclaimed Historian Hayek , cite improved allocative efficiency inherently created by the free market and distorted by the Keynesian system, in which the government intervenes and often gets into debt in order to sustain growth. However, in my opinion, there is no conclusive answer to the age old debate, with the current accepted status-quo being praised or ripped apart dependent almost entirely on the state of the economy at any given time.
For example, the 1920s in the USA signalled a rapid change in society and consumption,with cheap credit being readily available to relatively high-risk customers, prompting an increase in Aggregate Demand and by extension an increase in Gross Domestic Product. Concurrent to this, the 1925 introduction of liberty bonds allowed the general public their first opportunity to invest in financial products and instruments , commodities which quickly caught on with the both the general public and financial institutions alike ; By 1928, 40 % of all of the money borrowed in the USA was "invested " ( read : gambled ) in the stock market. As we now know, excessive demand over a sustained period of time , precipitated only by overconfidence can only lead to a bubble , which, once the excessive confidence is removed, is disastrous. Once this bubble burst, the American economy , and much of the global economy, plunged into a depression of a magnitude which has yet to be replicated.
This of course all occurred in a deeply laissez-faire, free market economy, and it was not until the mid 1930s when Keyne's views received the attention they deserved.
As a result, one would be forgiven for thinking that we as a planet would have learnt the danger of free-market forces acting untethered, yet 80 years on, overconfidence has resulted in a bubble and subsequent widespread economic difficulties. For decades, people were hasty to purchase property on mortgages  which were simply unattainable for them,  a huge  problem  compounded  by these same mortgages being used to form the basis of financial products such as derivatives, which unfolded themselves to collapse corporations (Lehman brothers ) and entire countries ( Greece ).
Governments are now intervening ( Keynesian ). Following a period of rampant free market activity which caused a recession. Sound familiar?