Answer:
To answer this question, you need to know the context of the New Deal. Because of the Lassiez-Faire policies and supply-side economics that dominated the Roaring 20s, we get the Crash and then the Great Depression. Now, Hoover's initial idea was called Rugged Individualism, which is kinda like a tiger parenting situation. Don't rely on the government. Try to improve your own conditions. At first, this concept sounds good on paper right? But it turns out that the Depression was so dreadfully bad that government intervention was basically required (this can be debated) in order to revive the economy.
So in comes FDR, and his New Deal. Under his New Deal, America sees significant government intervention in the economy. He used a structure called Relief, Recovery, and Reform.
Relief: Programs that could immediately fix a problem caused by the Depression
Recovery: Programs that helped people get jobs such as the CCC and TVA
Reform: Policies implemented so a crisis like the Depression can never occur again.
So overall, there was a change in perception about the appropriate role of government: Instead of Lassiez-Faire economics and deregulation, the government should have a more significant role in the economy and the livelihoods of its citizens.
Note: (This is the perception that was created because of the New Deal. It is not necessarily my belief nor my opinion).