Facebook really started changing when people began accessing it way more on mobile instead of desktop, because then the feed became more important than your friends' profiles - that was around 2012, 2013, way before TikTok even existed. Competition with TikTok definitely sped up the adoption of Reels, but the transformation was already happening for years: first came sponsored ads in the feed, then Stories copied from Snapchat, and now short videos. The platform basically realized it needed to evolve or lose users, so nowadays it's way less about connecting with friends and way more about consuming content and getting hit with ads - what really changed was the business model, not just the interface.