if no one spend their bitcoin then bitcoin price will be too much high but then bitcoin adoption will be too much slow and no one can be get profit from bitcoin easily and then i think people do not take interest in bitcoin.
if no one spend their bitcoin then bitcoin price will be down, if no one spend bitcoin demand for bitcoin will falls .
The price of a bitcoin is determined by supply and demand. When demand for bitcoins increases, the price increases, and when demand falls, the price falls
If the transaction not happened means any currency value may go down. So you are right if people stop using bitcoin then the value of Bitcoin will go down and there is a chance to disappear bitcoin. Now the BTC price is near to 800$. So just guess how many people are doing the btc transaction in the market.