Stocks Only Go Up - What role did apps like Robinhood, influencers like David Portnoy and government stimulus checks play in the emergence of Millennials in the stock market?

During 2020 the stock market was a "kangaroo market", with vertiginous and totally unexpected ups and downs. In a high volatility and liquidity context, there was an unprecedented increase in the number of retail investors, who started trading small amounts of money through zero-commission apps. Is this a new financial bubble about to burst? What role do apps like Robinhood, influencers like David Portnoy, and government stimulus checks have in this whole story? The answer is complex, but it is undeniable that something has definitely changed, and that something is access.