Last week, a judge announced that a merger between Sysco and U.S. Foods would be illegal. The order points out that a combined Sysco – U.S. Foods entity would dominate the market for broadline food distributors and give Sysco the ability to charge ultra-competitive prices.
How does Sysco do it? It's not technology. The URL above describes system requirements for using Sysco's web application. Among other things, it states "eSYSCO does not currently support Macintosh OS" and "we highly recommend Internet Explorer version 6.0".
Technology does not change economic reality. From an economic perspective, Uber and Facebook have more in common with Sysco than they do with (name your favorite calendar app). These companies enjoy profitability today, not because they are technology companies, but because they have monopoly power.