IT/Business Alignment

I have a question for you: when did IT and business units fall out of alignment? In every organization I've worked for, IT existed at the behest of business units. Without a business need, there would be no need for an IT department...or at least one of any size. Yet in those companies, there we were serving business unit needs.

Sometimes there were over 100 employees in IT and sometimes as few as 20. Regardless of size, the IT departments worked for the business units. Does this mean that IT was always working on the best interest of the overall company? Not necessarily. In cases where strong executive leadership drove the company's priorities, IT and the business units were perfectly aligned. In cases where there was chaos at the top and no clear direction, IT departments struggled to figure out how to best align with business units. Regardless, IT was serving the business.

Does IT/Business unit alignment mean IT is serving all the needs of all the business units? Nope. Sometimes issues that seem important to a business unit are not important to the overall organization. Small departments that, while they play a role in running the company, do not bring much to the table in the way of revenues or cost savings cannot expect IT departments to drop everything to work on their requests. Those department heads would say that IT is not aligned with their department.

So...even though I've read the myriad of books and articles on the subject...I'm still very confused about the apparent lack of IT/Business alignment. It's very odd.