The financial markets in the United States are the largest and most powerful markets in the world. The loosening of regulation in the last twenty years and the availability of inexpensive computing power has created markets that effect the lives of almost every US citizen.
Mortgages are packaged bonds and traded in a huge mortgage backed securities market.
This tends to assure that the interest rate a home buyer pays will be at a competitive rate. Many people have taken advantage of stock market gains via mutual funds. Venture capital funds the new companies, creating new jobs and wealth. Markets have their dark side as well. A time when some people got rich or richer while others lost their jobs and houses.