I imagine that some subset of users (1/10th?) would need to aggregate and serve their own and first-tier friends' content from a cheap VPS, and the Kardashians

I imagine that some subset of users (1/10th?) would need to aggregate and serve their own and first-tier friends' content from a cheap VPS, and the Kardashians and Elons of the world might need a CDN of some kind, but if it's limited to short text posts I imagine it would be a tractable problem.