Physical interaction is still extremely important to societies and individuals; not everything can be virtualized or made remote without loss of effectiveness or efficiency, at least not yet.
For personal interactions, you have face-to-face talking and generally (in the context of clustering) access to many people with aligned interests to talk and interact with in person in real time.
Culturally, you have art installations, exhibitions, and all sorts of activities like musical concerts, theater, etc. that aren't exactly reproduced remotely.
In terms of work and hobbies, clusters can give access to tools, workshops, that might be too expensive to have at home. Say using a hackerspace/fab lab vs. having a complete electronics lab in your house or a laser cutter.
All of those should be more readily accessible (in terms of transportation time and cost) if you are well located within a large hub.
Of course, remote does have significant cost benefits in some respects (housing and supplies), and for some professions the benefits of cities aren't strictly necessary, but clustering and the physical world should not be underestimated or thought obsolete.