How possibile see increase in future if it pass off exchange?
Market cap is related to how many bitcoins are already in existence * current price. It doesn't have to do with where the transactions are being made.
It does, as off exchange transaction do not have a influence on the exchanges rates, which is what determines the price currently.
All trading of bitcoins for other things affects the price whether it is done through an exchange or not because the supply and demand are still affected. Localbitcoin trades are off-exchange, but it would be wrong to assert that localbitcoin trades to not affect supply and demand and therefore do not affect the price.
What does it mean to be off-exchange, anyway? Suppose Bitstamp stopped publishing trade information. Would that make them off-exchange? You could even consider off-exchange trades to be on an informal decentralized exchange because buyers and sellers still meet and negotiate prices.