It's really impressive how successful this is. When Insta released stories, it basically plateau'ed Snapchats growth, and I wouldn't be surprised to see it happening to TikTok, at least somewhat. Meta always does this: develop the new format, expand availability and user saturation while being under-monetized (which impacts margins), then slowly ratchet up monetization until its as well monetized as existing formats, but with a slightly increased app-wide usage. You can see exactly when they announce the margin impacts of new formats on their stock price, and then you can see when they announce the full-monetization through a rebound.
As an occasional TikTok user, I'm baffled when someone says "no need to get the TT app, it'll be cross-posted on insta reels a few days later". But it's what Meta is counting on. I've started to see the same thing with YouTube Shorts. I personally wouldn't bet against Silicon Valley giants to stamp out TikTok or at least relegate them to Snap's precarious position, if through nothing else except through deferred monetization. TT has been aggressively monetizing, and its driving people away.