Lovely thread idea, Tupp!
It's wonderful how you were able to look at a very nice few hours with a friend (that you initiated) and see them as "a very nice few hours." Over time, with one person or another, a few will begin to take a more solid shape. And there's NOTHING wrong with discussing reciprocity in a calm way with new people.
Just as a getting-to-know-you subject people sometimes talk about. Every person you meet has had some situation in their life that has felt out of balance in that way. Every person you meet has felt hurt or lonely or left out sometime.
Sometimes these days when I meet a new person, we can find ourselves talking about making friends as adults, and how that's different for older people. I'll say something like, "I know people can make new friends at any age, but I've noticed it's harder now that I'm XX years old and in a new place, with a dependent adult child. I've really enjoyed meeting you and the XX group folks!" And then in a bit you could say, "One thing I've figured out is I want reciprocal friendships in my life. Not 50-50, nobody can manage that...but enough so you know the interest is mutual. You know what I mean?"
(I promise, the other person will say, Yes...) Then, back to you...
"How about you, how does that work in your life?"
Some people will be open and even eager to talk about friendships. I think it's especially helpful to talk about it consciously before a pattern is set. Practice on the new people! If someone seems to avoid the subject, then no harm no foul...they're just maybe not a good candidate for building a reciprocal connection.
I'm excited for you Tupp. Remember never to take any individual event as proving a global negative. Let it keep coming and going with more people, and expect more and less effectiveness. It's the pattern you're changing, not the particulars.
love
Hops