Subpar subsites – the benefits of flat architecture
Site collections define many boundaries in SharePoint on-premises, not least of which was a place to build subsites. Subsites are still an available option in modern sites, but hubs provide a more flexible alternative. What made subsites such a popular option in classic SharePoint? I think more than anything, they were the only self-service option when site creation was otherwise disabled. Even if admins had disabled site creation, users could often still create a subsite within a site collection they were a member of.
In addition to that, it really was much more difficult in SharePoint on-premises to have two site collections share information with each other. Often, the answer was to create subsites in places where they could work with other sites, even if the hierarchy didn’t fully make sense. Once a subsite was in place, what if you needed to move it to another site collection?
Aside from a migration tool...
