My degree is in business administration, with the equivalent of a minor in economics.
Economics is not an exact science like physics. There are many principals on which people who have studied economics generally agree. However, there are too many variables to pin down. Also, the economy is greatly influenced by psychological factors.
There is no way to quantify accurately the effect that the stimulus package had on the economy. However, there is good reason to believe that without it, we could be far worse off. If the bailouts had not occurred, we could have had a situation comparable to the Great Depression. But, since we cannot turn back the calendar and try something else, we can quantify very little.
Before the Great Depression, our economy had rapid and extreme ups and downs. The modifications to the banking system which were implemented beginning with the Great Depression dampened the cycles and resulted in more steady growth. Also, anti-trust legislation and other changes implemented beginning in the late 1800s resulted in a gradual decline in the gap between rich and poor.
Obviously we have made some mistakes. No financial institution should be "too big to fail," and it may be that the failures could have been prevented without rewarding the gambling bankers.
We will get through this economic problem. I hope that effective steps will be taken to prevent a recurrence. Specifically, there should be NO financial institution that, by itself, can have such a drastic effect on the economy. Also, income disparity has greatly INCREASED since about 1980 to the extent that it is far greater in the U.S. than in other prosperous countries. Perhaps shareholders should have to approve bonuses and salaries for executives of large countries.