Big investor are not only investor they are group of wheals and market manipulator ( Fud/Fomo creator) they know how to gain their profit and manipulate the world market sentiment they know well what they are doing, So why they are not attracted?
Based on what you said, I would say something about Bitcoin ETFs. Bitcoin EPF is a slightly centralized way of holding Bitcoins. Who holds Bitcoin through ETFs? I have seen people holding Bitcoins through EPF instead of directly investing in Bitcoins because they are more interested in buying ETFs than buying Bitcoin directly.
Great investors understand the market well, so they know when to buy something that will be profitable for them. You will see that it has been allowed for a while, but it is managed by big investors who have taken a lot of interest in it, and now you understand why.