Which Factor is Most Important to the Depression

I think the most important factor that contributed to the depression would be the new inventions. The poor people would buy all these products, a lot on credit, which they couldn't pay back and they had to borrow money from the banks which eventually closed too. Also, the companies would get really excited about people buying their new products, that they would bake too much inventory. They wouldn't make a profit because no one was buying their products anyore and they would waste their money.