I’ll tell you something you missed:
Steam’s DRM is notoriously easy to bypass, allowing that. They also don’t force DRM on their platform, it’s entirely developer/publisher opt-in (and they are also free to add additional DRM on top if they wish), and many many releases on Steam run fine directly from the executable without the launcher running.
Edit: For the record, I pirate before I buy, buy on DRM free platforms (GOG mainly) where possible, and use a third party launcher to unify my collection across multiple storefronts and many many loose executables into one spot.
Yep, Valve also normalized microtransactions significantly through TF2.
Once again, Valve started it as something reasonable: Cosmetic options, then expanded to allow shortcutting unlocking alt weapons through $1-3 charges instead of through game progression (achievements unlocked alt weapons at first). Other companies followed suite in ever increasingly predatory ways, and Valve got worse with it too over time.