Then say 'hi'. By definition they're not going to seek you out nor are they going to be findable so you're only option is to say hi to everyone and hope one sticks.
edit: heh i hope you're not talking about me, i walk to the grocery store regularly by myself. It's how a take a break from work and get some exercise. i'm fine :)
One of my ideas was legitimately to just hold a giant sign that just says "hi"
I had this idea a few months ago, but never wanted to waste a whole Sunday on it. Maybe I should.
Imagine TikTok asking you "you've scrolled for 30 minutes. You might be in a loneliness spiral. Write down the name of someone you would like to be closer to."
Imo short form video with infinite scrolling is straight up poison and it's impossible to resolve without just completely destroying it.
But ultimately, if a man is sitting in his kitchen and its on fire. Its up to him to run out. No amount of reaching out will help until he decides to make the change.
As long as leaving the house and making real contact is harder (requires more self discipline) than staying in and scrolling, all you can do is project a message to folks at home, like "hi, you're not alone in feeling lonely," but you haven't solved the fundamental problem: it's harder to do the right thing than it is to do the wrong thing.
To solve the loneliness epidemic, you have to make the right thing easier than the wrong thing. "Reaching out" to more people will not accomplish that. Elsewhere in this thread, you've rejected the idea of pursuing a public policy, but policy is the only answer anyone's provided in this thread that could make that happen.
(Now, it turns out that you'll have to do a lot of outreach to make a public policy happen, but you'll be asking for their vote, not a regular commitment to show up weekly at a club; outreach is the right approach to that problem.)
The only time you ever see such people is when they're walking to the grocery store. How do you reach out to them to let them know about these ideas or encourage them to try it? Especially when they're filled with discouraging thoughts?
What if all they need is one single person to say hi? How can I find them, reach them? This is what I'm asking.