You need to understand that mainstream does not mean that a few institutional investors are holding 3% of BTCitcoin in circulation. In my view main stream should mean when majority of people enters the market and not just when a few institutional investors hold majority of the coins.
The rally is based on these institutional investments in the past one year and some of the multi national companies are trying to incorporate BTCitcoin in their business.
I am kind of confused in this one, there was a thread about this about the amount that the institutional investors are hodling and it was around <=1% so I can't believe this number exactly because there is a conflict. For me, mainstream is a combination of the companies and the public adopting bitcoin. We can't really blame that they buy a lot of bitcoin because the public individually is very weak and can't afford a lot of bitcoin. Can't be worried about it though, as more of this companies continuously buy bitcoin then the more the price increase because there are less in supply.