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So my question is what happen to those crypto when the owner of such wallet is no more and no one has access to such wallet?
Yes, nothing special happens. These are dead wallets with dead coins. No one will ever use them (by the way, for example, in the TELOS blockchain there is an opportunity to burn such coins over time).
And for the case of a testament cryptocurrency is, for example, the service MyWish (with "Will contract" - Transfers persons savings to his family or friends in the event of his sudden illness or death).