Michael Saylor of Strategy believes Bitcoin could reach a price of $21 million.The cryptocurrency market has historically been driven by passionate retail investors. In recent years, however, several high-profile executives have also started embracing digital assets.Tesla CEO Elon Musk has frequently joked about Dogecoin, while Ark Invest CEO Cathie Wood has consistently voiced strong optimism around Bitcoin (BTC 0.94%). Another corporate leader who has gone even further is Strategy co-founder, Michael Sayl ...