PlanB, the widely-followed anonymous cryptocurrency analyst who first applied the stock-to-flow ratio to the Bitcoin price says, “The model is not built to last forever.” The model, which tracks the circulating supply of an asset against the amount of new supply hitting the market has proved remarkably accurate for tracking Bitcoin’s past price action. Using the model, the outlook from PlanB indicates the BTC price could hit $100,000 sometime around the year 2021 and break $1 million around 2025. But in a new series of tweets, PlanB says he’ll be happy if the model maintains accuracy for the next two to three more halvings, which is the equivalent of about 4.5 to 8.5 years.