In my experience, FB and others moved away from being about your friends to become content sharing machines long time ago. It’s like reddit but without sub separation + influencer glamour.
Tiktok on the other hand came from purely creative angle. It’s not about your friends, it’s about using creative tools to express something. That’s why TikTok dominated the original new content market. TikTok’s editing tools are phenomenal and people are using them so creatively.
IMHO, the traditional social media giants optimized for profit only, destroyed any potential competitors and up until TikTok we have been left to terrible state of the social media.
If you recall, FB and others were involved in political manipulations and accused of spreading extremism.
It might seem like long time ago but American-made social media was riddled with conspiracy theorist and white supremacists and the tech giants were blamed for spreading that in the name of engagement. At some point the place has become so horrible that they started blocking prominent accounts, including the American President.