Earlier quoted context omitted.
Everyone I know in my age group with a house got help with their down payment from parents. Either in the form of low/no interest casual loans or just substantial gifts. It's possible this money wouldn't have been available to them for speculation in the stock market.
Some of us don't have parents who have more money than we do.
For instance my girlfriend makes twice the money her parents ever did. She still couldn't have afforded the full down payment on her house without a 4% loan from her mother as they were entering retirement. This arrangement ends up being beneficial to all parties.