It may be delusional to not deal with the software is viewed. But the thought that it's strictly a cost is itself a delusion. I have seen firsthand corporations being choked by bad software. (A certain cell phone manufacturer and a certain car rental company come to mind.) I've also experienced good customer service enabled by flexible software, where I'm amazed, "You can really do that?"
Amazon wouldn't be nearly as good as it is if it wasn't for the degree of software quality that they have.
I understand your point and I agree that software could make or break a company. That can be true and you could still make the argument that IT is strictly a cost. That IT departments can enable other departments to reduce their own costs does not change the fact that IT itself is a cost.
In your customer service example IT has clearly had a positive impact, but you'd be hard pressed to convince anyone that the IT department is generating revenue for the company. If you walked into the CFO's office trying to make that case you'd be laughed out of the room. Good customer service does not manifest itself through good software.
A better approach may be to walk into the CFO's office and show how your IT department is helping the company realize it's goal of providing good customer service at an acceptable cost. It's a very subtle distinction. This is what I was getting at when I said not thinking of IT as a cost can be a roadblock to advancement.
Being considered a cost and providing a competitive advantage are not mutually exclusive. An IT department that meets its goals at a lower cost than an alternative could be a competitive advantage.
An example of an IT department that's a revenue-generator is Amazon's, in the sense that they sell services outside of the company. But that's quite rare. At most, some IT departments chargeback internally, but that's just made-up money.
Then again, I think it was Bezos himself who described Amazon as a technology company that happened to sell books too.
