Saylor is assuming (correctly, imo) that some of the "store of value" function of real estate and metals will move to bitcoin. Probably all of it will, eventually.

Look at some building near you and guesstimate the price of that building. Now consider how many similar buildings there are, how many are worth more or less. There are around 6 billion buildings in the world. The total value they store is in the quadrillions of dollars. Its not comparable to total global GDP because GDP measures change, not value storage. Its quadrillions, not trillions, because each building is being used as collateral, meaning layers of loans are originated on top of that asset. And ALLLLLLL that value premium will move to bitcoin.

So... Saylor is actually super bearish. Maybe he's just cautious in front of conservative investors. He wants to convince them to buy mstr stock, not break their brains.