Markets have been regulated from the beginning.
Markets other than barter that use some form of exchange require a formal financial system to regulate the flow of savings, investment, the amount of exchange (money) in circulation, its value and its manufacture.
According to classical economics, interest is supposed to balance the demand for investment and savings. Therefore interest should fluctuate with the supply and demand of investment. This can't happen in practise under a system of financial control.
Savers reduce their current spending ability in anticipation of the need for money in the future. This means savers need liquidity. (Will Hutton, The Revolution That Never Was)
Investors need long term stability or illiquidity of money provided by savers.
This and other factors will lead to crises. When the financial system hits a big enough crisis the state steps in. The first measure the state will take will be to adjust interest rates. Next, it will increase or decrease the money supply.
The fact that markets need a formal and regulated financial system and that the financial system needs state aid from time to time means there can only be a limited free market. The market is limited in scope and time.
Markets are inherently cyclical becoming freer on the upswing and more regulated on the downslide.
Keynes recognised this.
Keynes wasn't the first to record this, a few years earlier Marxist economist Michel Kalecki wrote an analysis almost identical to that of Keynes' General Theory (An Attempt at the Theory of the Business Cycle 1933).
The British economist Alexander Cairncross was a student of Keynes and he advised the Chinese government how to build the successful demand based economy they have now. The Chinese government may call themselves communists but they operate a solid Keynesian system. The demand came from Britain and America.
The growth and success of China is a direct result of Thatcherism
In Britain ex-bankers like Sunak and Javid, who should know better, are harking back to the failed and failed again 19th century ideology that we can still call Thatcherism.