Considering a bitcoin owner of large amount, and he died w/o sharing his user/pw, Are those coins can be considered as deadcoin since those coins will not circulate anymore in the Network?
When that happens, many of the users here called that a lost coin and this coin will never circulate again, The bitcoin supply will truly lessen and if the supply is less, then surely the price of bitcoin will surge.
You are right but it can return into circulation when someone can accidentally access it but it very unlikely. In the future, I am sure there will be a way to recover those lost coins so I won't call it as being gone in the circulation forever. If someone were to own large amounts of Bitcoin though, it is impossible for him to just die without leaving a clue for his family in order for them to access his wallet.