Many people can go to a bar and fairly reliably get laid several times a month. That’s simply not possible for the overwhelming majority of people using TikTok. TikTok / Twitter/ Instagram etc are designed to be shallow interaction so people stick around. Dating apps fill that niche, but also want people to come back.
Being in public allows for the full range of relationships in any setting. You can meet a great friends at a bar etc.
In forms of social media that existed primarily to produce inter-personal connections (i.e. very early Facebook, or maybe even LinkedIn) your argument works significantly better, but the way that instagram/tiktok/etc prioritise influencers in your feed makes the likelihood of 1-to-1 interactions infinitesimally low (unless you yourself are also playing the influencer game)
Maybe introducing yourself in-person is slightly deeper than thumbs-upping someone's video, but by the same token the latter is a smaller step; you can always go with a full-sentence comment or a video response of your own if you want the slightly deeper interaction.