With Guesstimate, users could create "organizations", where they could share their models with each other. For example, see the Guesstimate group.

https://www.getguesstimate.com/organizations/1

Lots of applications, like Notion, Github, and Asana, have similar ideas.

One potential issue with Squiggle Hub might be that people might use this feature to cluster models together, instead of to share with specific people.