Forgive me if I'm totally wrong, but it's copyright law, right?
TikTok lets you put current popular music on the videos without a care for copyright, correct? As they are Chinese, they don;t really care about any lawsuits. The same is not true for US based companies, thus they don't have as good of music on it.
TikTok pays a lot money for the popular music, they are all licensed so users can use them for free. New artists make more money on TikTok than other platforms.
I'm pretty sure ByteDance does license music. I don't know if they license all of it, but I'm pretty sure the RIAA or ASCAP could easily get an injunction if they didn't license any music that was theirs.
They do license the music, it's very ham-fisted though. They just pay out huge lump-sums to keep PROs happy. I've heard they're trying to build something more sophisticated like YouTube's Content ID system to get more accurate numbers on who/how much they should be paying.
TikTok lets you put current popular music on the videos without a care for copyright, correct? As they are Chinese, they don;t really care about any lawsuits. The same is not true for US based companies, thus they don't have as good of music on it.
Also, again, sorry if I totally wrong here!