When you loses wallet, it has the effect of removing money out of circulation. Lost bitcoins still remain in the block chain just like any other bitcoins. However, lost bitcoins remain dormant forever because there is no way for anybody to find the private key(s) that would allow them to be spent again. Because of the law of supply and demand, when fewer bitcoins are available, the ones that are left will be in higher demand and increase in value to compensate.
It's lost forever. The more people who lose Bitcoin are effectively giving it more value.
Is there really no other chance to recover it? Well even though they've lost a wallet they will still have contributed in increasing the value of BTC. Now I know one of the reasons why btc is getting more popular. I just hope there will be a way to recover lost wallet in the near future. It's really sad if those wallets has a huge amount of btc.