OK. I can tell you exactly how much money is flowing into bitcoin. It is $75,000 per day.

This is the number of new coins mined each day * the average price each day.

Sideline money is a myth. All the buying and selling of existing coins means that for every dollar in there is another out.
What makes the value go up is sentiment. For a disruptive technology which has the capability of displacing fiat currency $75k per day is absolutely peanuts. Wait until people with really deep pockets get involved. $10 million per day could easily flood into this market - absorbing the number being mined.