In addition to that forum archive, here’s a Steam support response via Reddit: https://www.reddit.com/r/Games/comments/18mzcn/i_asked_steam_support_what_happens_to_my_games_if/
Gabe Newell has promised that if Steam goes down you won’t lose your library, but we only have his word as assurance.
I didn’t even catch it when I read the article
I installed Fortnite to check out the LEGO mode without realizing EAC was a rootkit and the next Windows update bricked my PC.