Video game pirating was mostly killed by viruses. At one point it was too just too risky. Probably good sources still around but it's too much hassle, maybe only if you game a lot and don't have a job to pay for a hobby.
It wasn’t, teenagers don’t give a shit, and torrent sites like Piratebay had trusted uploaders (green/pink skull) and comments.
Steam sucked initially but it kept increasing its value add (cloud saves / settings sync, easy voice chat before Discord, Steam Workshop for mods, etc) and simultaneously the sales got better and better.
Why pirate a game when you can wait a couple of months to buy it for 66% off, niceties included.