People see different facets of our identity, only God sees all of them.
In some cases our limited online presence might represent a more authentic version of our 'true selves' than we present in [the rest of] "real life".
>"it will become near-impossible to find voices worth hearing" //
Isn't the OP saying there that we all have a voice worth hearing. You're right that it would be harder to find the voices we could extract the most value from; but realistically that's probably already impossible.