And some of them most certainly will (for a multitude of reasons)
Maybe not officially, but you never know what wall street people do with their personal wealth at a personal level... like, someone working in a trust fund firm may not get their firm involved, but they may speculate with Bitcoin themselves and not tell anyone. In fact this is happening right now, bankers and professional traders own Bitcoin, they just don't say it in public.
What are your sources?
Personally, I don't believe in such stories. Wall Street tycoons are not fools in general. This doesn't prevent them from making fools of themselves sometimes, though, but this is obviously not the case. They would "invest" into Bitcoin with one and only one purpose, that is, to get profits. I think it would be bordering on wishful thinking to expect them to do anything just out of some altruistic motives (for example, to expand Bitcoin ecosystem). It is apparent (at least to me) that many hope that their money if poured into Bitcoin would boost the price, but usually they are not the ones who is profited from...
In other words, they don't put their money into what otherwise would be a Ponzi scheme