I think : for developers used to work on SQL Server, they will more likely see "Database" as one components of an application. So if there are many applications running in your organization, there will be multiple "Database(S)".

In that case, I think schema may have little value. As in that case the boundary of every applications will naturally base on database rather than schema.

However, if "Database" resume its original meaning as it first appear, where it should be a consistent information source for different applications, each provides a unique information usage of its kind in an organization, then schema can help to make such boundary easy to be administer.

I know that as nowadays, most organization may run applications built by different third party. Each application vendor will like to have absolute control on the database behavior. So a single Database to support all information requirement of an organization seems far from the truth. Neither will such centralize approach helps to scale the database to meet the needs of the organization. It may even cause recovery and availability issues to exaggerate to another order of magnitude of difficulty.

However, the rise of database is also the cure at the time as it appear to overcome the problems from isolated data source, excessive replication of data, and lack of consistency among data contents. When we see there is all kinds of challenge in integration, such decentralize approach to database may also reintroduce the problems as the cure originally aim to solve.

For me, schema is more likely a tools used in managing diverse data in a centralize database environment. Perhaps its importance may also gone as the database nowadays is no longer the database when it originally proposed.

Rgds,

Eric