Amazon does not dominate the market that McMaster-Carr exists in. It's not even in the running. If you attempted to use Amazon for the type of project McMaster-Carr exists to support, you're going to get laughed at at best. MMC/Misumi/Grainger/etc. own industrial/mechanical, Digikey/Mouser/Arrow/etc. own electronics, RockAuto owns automotive aftermarket, etc. It's actually incredible how little fight Amazon has put up in these markets.