Every lost Bitcoin reduces the number of Bitcoins in circulation. The scarcer it gets, the higher the value per Bitcoin. So in a way every Bitcoin owner benefits from this.
I don't think this is true, the impact I mean. For the lost supply to influence demand wouldn't the market need to be aware of it? And the market can never be aware of the lost supply.
Maybe it's the fact that the fraction of people who would have had those coins are no longer participating in the market as sellers that really influences that supply vs. demand equation.
Any economists out there care to comment?
Exactly, market is only aware of it through the supply/demand of the guy who lost Bitcoins. Considering he will not be able to sell the lost coins at some point, this reduces future supply and consequently increases the price. Also, he might want to purchase more coins, because he lost some, so that increases demand and again the price. So lost coins do not influence supply/demand by itself, the guy that lost them does.