I've been on Medium since 2015, and I know what you mean, Ruby. When I'm looking at old stories of mine, I will see ancient highlights and responses from people I have not heard from in years — and that doesn't include people who have cancelled their Medium sub (or been cancelled, in a couple cases) since they simply vanish.
There are a few folks who I know have died IRL, but their comments still persist. It makes me happy/sad to read them — like a part of them is still alive, but it's a reminder that they are not. Not really.