The curiosity is great but the process doesn't work as you described. The coin never disappears or shortens supply. As soon as the coin is bought its ownership changes hands, instantly. Likewise, if you pay me for services the coin becomes one as soon as you tell you wallet to send me the coin. The length of the transaction is akin to the time it takes for me to mail you a check or for you to accept a Venmo payment. It has zero influence on the ownership or supply. So the supply doesn't decrease, therefor price can't be moated for this reason.
It's great thinking though.
If you read my use case carefully, you will see that during the whole phase of this trade, Bob's one bitcoin is not available on market, that is the decrease of supply. This is nothing new for those who knows quantitative theory of money, I just analyzed it in a more detailed way
However, in fiat monetary system, many transactions are done inside the same banking network, banks using daily settlements to hedge the real move of the money during a day and then mail a check does not change the money supply since it never touches the real money, only changes banks account numbers, just like when you trade bitcoins in an exchange, only numbers in your account changes, bitcoin never moves until you withdraw
You can look at an extreme case: I want to transfer 1 billion dollar from US to China, and I bought 1 billion dollar worth of bitcoin on exchanges, at current market price it will be 3 million bitcoins, and I might end up bought most of the coins available on market. And during the time those coins were under transition, the exchanges around the world will have much less coin, say 1000 coins available for sell. If another user comes after me and want to transfer 1 billion dollar, he has to pay a price of 1 million per coin to achieve his goal