Oh but you have to know the schema right? Yes, some other part of the application knows the schema, but this part doesn't have authority over the DB. Also, the schema may be data as well.
NoSQL reduces the work needed for that.
But why would I waste developer time doing that if I can only do db.table.insert(obj) - in MongoDB for example (obj is a JS object)
Also, finding all objects with a field named 'field1' and value '3' is slower if you do that in a relational DB (and that's the simplest case)
The fun thing about NoSQL skeptics is how they think of only the current scenarios they work with, and they won't believe you until they get burned by it. So be it.