Some closeness survives because someone keeps finding a small practical way to meet.

Long friendships are usually held together by logistics rather than by feeling. Somebody works out that the halfway town has a decent cafe, that Sunday mornings are free for both, that a walk suits a person who cannot sit through dinner. That effort is invisible and entirely decisive; without it, warmth alone quietly turns into people who used to be close. Fondness does not schedule itself.

If a friendship matters, take on the arranging for a while without keeping score. Look for the version that fits both lives rather than the ideal version.