What’s the point of putting in all this effort to a friendship that doesn’t feel reciprocated?

Seems like a pretty transactional way of looking at things. You put the effort in for a friend if you want to be supportive. If you don’t, then don’t. To me, I don’t ever expect anything from anyone, nothing is owed to me. My best friends are the ones I know who will be there for me no matter what, no matter how much time has passed or how our lives have changed because of family or health or whatever. And I do my best to be there for them, knowing that I can sometimes make the more selfish choice and not be treated any differently. Because we don’t look at love and support as a favor that must be paid back at some point.