Adam Back believes that BlackRock's 2% Bitcoin allocation within diversified portfolios could drive the price of BTC to $1 million.Limited supply and increasing institutional demand are viewed as key factors in potentially pushing Bitcoin's price to seven figures.Bitcoin ETFs and growing interest from traditional finance institutions are contributing to the rise of institutional demand for BTC.Experts like Michael Saylor also foresee mass adoption by money managers as inevitable, supporting long-term bullish forecasts for Bitcoin.