Beyond GenX and Boomers who is still using Facebook? We don't live forever.

The last time Facebook reported its monthly active user base they were at 3 billion. [1] So I guess the answer to your question is… everyone?

[1] https://www.sec.gov/Archives/edgar/data/1326801/000132680124...

How many of those are real people?

Every bot

A lot of people use it for Facebook marketplace

But what's being discussed isn't usership: it's stock prices.