Here is an example:
Marry has a lemonade stand. Marcus has a lime stand.
Both are fruit that people drink; however, Marcus can't get sales due to low demand of lime flavored beverages. The neighborhood head feels like that lime would be better for people because it has less sugar than lemonade. So, the head gives Marcus money to make more limeade for customers, following Say's law: Supply creates its own Demand.
Pretty soon, Marcus is able to drive up sales.
Now, those who favor the neighborhood head agree that Marcus deserved the surplus. There are those who did not favor such expenditure. Marry's sales begin to hurt. Marry cannot do anything except wait for the 'market' to take care of things. Now, Keynes law comes into effect: Demand creates its own Supply.
Marcus has only enough resources,( land, labor, capital and/or entrepreneurship,) to make certain amount of limeade. Pretty soon, high demand and low supply drives up prices. Marcus therefor cannot compete with high prices against Marry, so others go to Marry because she has a cheaper more available products that was/in not inflated.
The analogy hopefully is clear: Marry is oil, Marcus is AE. When the neighborhood head, ( gov't) gave money to Marcus (AE), they drove up prices by messing with the market. The principle of economic stability does not play into effect when and initial investment is made. Why do you think we have regulations in private transaction?
This is the best I could do. Other than that, ask your local economics major about such thing.
dogman out.
P.S. I do think that the govt can positively influence the market. They just need to stop playing ( place favorite sport here).