Just like most people's bank balances don't really exist. Banks aren't just sat on hundreds of billions of dollars for every deposit that people have made.

You're right in saying that bitcoin do not exist in a tangible sense but if you're suggesting this is an issue then I neglect that idea outright. We are moving ever-steadily to a digital world, not just in finance. The approach of bitcoin is superior to traditional payment methods and mintable coins in numerous ways.