Even if RT removed their limits, there are still government imposed ones (supposedly to protect unsophisticated investors from risk): https://en.wikipedia.org/wiki/Accredited_investor#United_Sta...

RT's limits are much higher though, and that probably is done with the goal of limiting the number of individual investors. Dealing with investors is a distraction for the fund managers. But the main issue is proprietary information. The more investors you have the higher the risk of information leakage to your competitors.