Earlier quoted context omitted.
Thinking about your last statement: If the price were an average of beliefs, we would have people that believe it's worth more and people that think it's worth less. Those that think it is worth more would, logically, buy Google stock, and then the price would increase until we reached the price where people are somewhat on agreement that it isn't worth more. So, either there is a lack of funds to make the purchases,…
Every stock trade reflects a disagreement between two parties about the value of the company, not an agreement on what it is worth. The buyer would rather own that stock than that amount of money. The seller would rather have the money. They can't both be right about which is more valuable.
Actually, they can. As a simple example, they can agree on both price and volatility projections, but simply have different utility functions in terms of how much volatility they are willing to accept. Most simply, one of them might be 64 and about to retire while the other is 22 and just starting to invest in their retirement fund.
I expect that a majority of stock purchases/sales are in fact driven by such considerations and not fundamentals analysis...