To answer this accurately, it helps to clear up a common distinction first: Steam and Windows aren't direct competitors—they exist on different levels. Windows is an operating system (OS). Steam is a digital storefront, community platform, and game launcher that runs on Windows (as well as Linux and macOS). Because virtually every game on Steam is built to run on Windows, Windows as an overall platform naturally has every Steam game, plus thousands more available through other storefronts (like Epic Games Store, GOG, itch.io, or standalone launchers like Riot/Battle.net). However, if we compare the Steam Store directly against Microsoft’s built-in Windows gaming ecosystem (the Microsoft Store & PC Game Pass) , the dynamic becomes much more interesting. 1. Quantity: Steam is the Undisputed Heavyweight When comparing catalog sizes directly between stores, Steam overwhelmingly dominates Microsoft's native storefront. Steam Sto...