I have worked at a Fortune 500 company for almost five years. A few things I have observed there:
1. Most businesses larger than, say, fifty employees are going to have very complex problems -- problems that only dedicated IT personnel can solve. I fail to see how any outsourced "mashup" (whatever that *really* is) could tailor itself adequately to these problems. It's just a restatement of the common problem of customizing third-party vertical software for a specific business. In my experience, that endeavor tends to faily miserably, draining productivity as users are forced by the software into a non-intuitive mode. Eventually, the offending system is removed and replaced with something else. You need IT personnel for all of this.
2. In a large IT group, there are a lot of people who don't contribute value. You have your sycophants, ass-kissers, hiring mistakes, misassigned resources, bumbling managers, etc. The problem is that the corporate culture can make it very hard to get rid of these people. They may have influence with the powers that be, or they may even *be* the powers. If you see some downsizing, you have to ask *who* got downsized. Perhaps it wasn't the people actually adding value.