(caveat: I'm a developer but I haven't used ORMs very much.)
Don't most ORMs let you write raw SQL when you really want to? In that case, you could use the ORM for simple things, but revert to raw SQL when you need more power. Or is that not the case?
Yes, but the ORM often influences the schema design. That can be very painful down the road when you realize your tables are actually tables, rather than instances of objects, which would be what your ORM led you to believe.
I think the problem is not that an ORM often influences schema design, it's that Relational Databases/SQL often influence application design.
People complain that an ORM isn't using a relational database effectively. The greatest contribution of the rise of ORMs is that relational databases are hard to use properly.
No you have it backwards. RDBMS are as they are because maths (relational algebra and calculus). There is deep theory behind doing things this way. You can put data in without needing to know how it will be accessed and used (and vice versa). NoSQL just doesn't have this rigor. You have to tightly couple what creates the data with what consumes it. THAT is just begging for trouble down the line.
That is absurd. Saying that using a certain data access api tightly couples you to it is as crazy as saying using variables tightly couple you to ram (and using ram is obviously bad!).
I honestly don't think you understand what tight coupling means.
You have data. To access the data you use an api. SQL is forcing you to use a generalised API, which is very old, hard to use and more importantly; hard to test.
If you actually want rigor in your SQL API, you use stored procedures. So now you're maintaining two languages (SQL and stored procedures) in addition to your application language.
For me, for most things, I just write a webservice which talks to whatever database I want. That's the API I expose. Anything can consume the API as long as it follows my RESTful spec.
With this architecture, I;
1) Don't have to struggle with SQL, making development faster.
2) Don't need a DBA making development cheaper.
3) Get to write in one language making testing a lot easier, which in turn makes quality higher.
4) can scale easier, picking whatever data storage characteristics are important to me.
Lastly, saying that NoSQL just doesn't have this rigor really makes me wonder what you think of google's bigtable or amazon's simpledb?
Don't most ORMs let you write raw SQL when you really want to? In that case, you could use the ORM for simple things, but revert to raw SQL when you need more power. Or is that not the case?