I hate to break it to you all, but unfortunately, rampant speculation, the hack attacks and massive price drops have already essentially killed bitcoin from the credibility point of view. No large company will willingly use a currency if using it risks their profitability on the scale bitcoin does.
This was back when bitcoin was a haven for criminal enterprise and crazy speculation rides. It was ludicrous to consider any respectable entity getting involved in Bitcoin and yet... here we are.
Do I think governments or Wall Street will get involved in Monero?
Hell fucking yes I do, especially once they realize how much better it is than Bitcoin.
I can definitely see governments getting into Monero due to the ability to be secure in transactions of money to one business/government to another... but do I see it being a big player on Wall Street? Meehhhh... I don't really know about that. It's not like Wall Street would want to use monero for any reason because why should they care about the anonymity of the transactions, and I wouldn't really see Wall Street wanting to put it in the market because, well, they want to keep S & P all fiat based.