What useful things are you talking about and is their evidence of their decline?
- talking with strangers at the grocery store
- working on my novel
- building things in my garage
- antagonizing institutions that I think have crossed a line
And those things are meaningful to me in ways that being on social media is not.
As for whether such activities trickle up into some kind of high level aggregate good, I don't know, but it's not hard to guess at how they might.
What useful things are you talking about and is their evidence of their decline?