Because you would be paying for goods and services with fiat just like today - but the way the companies work will be much more efficient because of blockchain technology. The cost of running the systems are initially paid for by the companies. Eventually it is of course the consumer who pays, but because of the savings blockchain brings this means that the consumer in total will also see savings. Same as with the internet. The companies spend millions on their webshops, and consumers do not pay to be allowed to use the webshops, that is just part of the product price.