> A bit of SQL in stored procedures on top of a DB is good enough all the time.

You do need an HTTP server if you want to offer an HTTP service.

> Heck, why don't we just let the users get what they want by giving them access to a SQL prompt.

I don't think any RDBMS has a sufficiently complex permissions system to accommodate the needs of a webapp.

> We could eliminate the UI completely.

Obviously, any user needs a UI to interact with any software, so I'm not sure what you're trying to say here. Your proposed SQL prompt is also a UI.

I feel you're trying to imply something here, but I'm at a loss as to what that is.