Not really no, even if the coins were permanently lost, it just means that the available supply would be reduced. It can even reach the point where we would use smaller units of Bitcoin such as satoshi to count the amounts (or maybe even smaller) if need be. There's nothing really wrong with the intended 21 million I must say, even if we lost hundreds of BTC, the network would still run faithfully since the price would naturally adjust depending on the total amount of available supply together with the demand.