One reason someone might sell is that he/she just inherited a million or so shares, and for estate settling reasons, needs to sell the stock pretty quickly. With the low daily volume, such a seller who is gradually feeding out shares to sell every day, could hold the price down for a while.
The point is, there are always many different stockholder situations that could make someone sell now regardless of future prospects for the stock. They tend to hold the price down. When volume picks up heavily on a price uptrend, these people will be flushed out quickly. Then the p/s should better reflect value.
Food for thought.