I only have my anecdotal experience to draw from, but I've noticed that having a network of strong relationships is the one factor whose impact on my happiness hasn't seemed to dull over the years.
I think you are right. Might be because such a network is flexible, provides what you need, when you need it, and it only appreciates with time. Unlike say a car or a new phone which quickly depreciate and rarely adapt (can be adapted) to your future needs.