Steam is a store, for software. Extremely popular store for that. They make technology, but their main income is selling games made by others, digital collectibles derived from these and then collectibles and lootboxes for their own games.
None of that is "tech" as I would understand. No one is for example paying them for their work with Proton to make Windows games run on Linux. And I don't think there is even such market.
Steam provides a great deal of utility for people selling games on their store via technology. DRM for example is technology, but so is validating installation, checking for updates, etc.