I don't see that happening.
U.S. customers and ads, are going to move to Facebook, Youtube, Instagram ect.
Facebook is ancient. YouTube serves a separate niche.
Instagram is losing popularity.
Instagram has about 2 billion monthly users.
Youtube is raking in the highest portion of ad revenue.
Facebook and Youtube are more profitiable than TikToc.
What TikTok has can be duplicated, including its operstional model for content creation ect.