I haven't researched your other points but I know that number six is in error. The twenties were not a period of high savings or high domestic investment. Historians note it as a period when few 'middle class' individuals and no lower class individuals saved money. 'Investment' came from the high end of salaried individuals. People did rely on families and relatives to take care of them in old age. That's because they didn't put money away. That's because they didn't have the extra to put away. The stock market crash of 29 was characeterized by a world wide depression. I differ with your other point in number 6. What is fueling the economy in the U.S. is the rate of savings which is much higher than in past decades, although still low by world standards. The baby boomers are socking it away. In bonds, in funds, in stocks and even in C.D.'s. That's one of the reasons why the market continues to head up when reason would indicate that people should rethink some of their investments. Employees have 401(k)plans, profit sharing plans, 403(b) plans, traditional IRA's, Roth IRA's and just plain old savings. Lots of money and it has to go somewhere. The problem is coming when all of these people start to take the money out and are no longer contributing due to retirement.
Anyway, those are the facts, and I can quote sources.