Many times in my life I’ve felt disconnected, lacking the friendships I desire. At a distance from old friends, geographically and emotionally. It hasn’t been simply bad luck, or dastardly actions by others. (And if I focused on those things, what could I do about them? Very little.)
Speaking for myself, disconnection has followed from my neglecting of relationships, of the people I’ve cared about and who have cared about me. It has resumed from unclear or misguided priorities. Allowing distractions to govern my time. Lack of social awareness. Lack of conscious, planned commitment to guarding and maintaining friendships. Unwillingness to be vulnerable and own up to my desire for friendship. Fear of taking initiative in making new friends. Low energy due to bad habits and poor management of my health, meaning a lack of spare energy for social activities.
Those things allow friendships to escape, and as time flows on, an untended friendship will escape.
Planning time for friends, keeping in touch over the years and willingness to be vulnerable: these bring friendship closer.