I don’t know if what I’m about to say is right or wrong, but I do think that if a certain number of Bitcoins happens to get missing, then it will lead to an increase in the price of Bitcoin. Why I’m saying this is because there will be lesser supply of Bitcoin, and since the lesser the supply means bigger price, there should probably be an increase in price, and then we will all be buying in satoshis.
In general, yes. Over time, the number of bitcoins will steadily fall due to the loss of access to them for various reasons. Already, about seven million bitcoins have been lost. However, at the same time, I think that technologically, ways will be found to restore them. Otherwise, indeed, Bitcoin is rare. Given that over time the number of different types of cryptocurrency will increase, it will not be a big problem.
There are total of 17 million Bitcoins mined, and based on the research I have made, close to 4 million Bitcoins are likely to be missing and not 7 million like you have said. So that means we currently have about 13 million Bitcoins or so trading in the market. The number of Bitcoins to be mined are remaining about 4 million.