Olle P :
CaptainTom :
Mining runs the transaction and ledger network these coins run on. ...
... and once mining of a specific currency become too expensive to make any profit there won't be any mining. Transactions might become very difficult to do. The value of the currency will most likely drop to (very near) zero.
Good lord when will people like you stop harping about how Bitcoin will be worth "near zero" any day now?
BTC is worth $4400, and it is nearly a decade old. It is here to stay grandpa.