The great impediment to gains in BTCUSD is the bandwidth of the pipe. It's just too hard to buy BTC.
The great impediment to institutional investment is volatility, which is the result of the price being too low relative to the amount of money that wants to move in/out.
It's a bootstrap problem. One way to resolve it is to increase the size of the bitcoin economy, resulting in more velocity, more churn, more liquidity and more price stability. That will remove barriers to institutions. Another way is to fatten the pipe, as e.g. by creating a BTC ETP. Entrepreneurs are working on both of these avenues, so stay tuned. (Or better yet get out there an innovate yourself.)