They don't know how to buy stock until they see the mainstream news say "download this app called Robinhood in order to buy this stock that will make you rich", which is why Robinhood rocketed to the top of the app store charts this week.

Most people do not tune out stories of the form "do this simple thing to get rich". It's the same reason endless coverage of the lottery gets good ratings.

Your mental model of how stock bubbles work is not accurate.