Background: I am a systems guys/developer. I develop a lot of intranet websites and apps used by thousands of people at my company (almost 100K employees globally).
For the most part my company prefers using vendors for projects. We spend months and sometimes years looking at vendors for various projects, I am tasked with vetting out the technical ability of vendors, and then some higher up signs a big contract with one. For every vendor that does a decent job, there are 5 that are terrible. Once they have the contract signed and get us "live" it is all downhill, and some can't get us "live".
My job focuses on two areas. The first is keeping the vendors in line. Basically people cc me on emails about vendor issues to make sure what the vendor is telling us is true (most of the time it isn't). And then I have to offer solutions to the vendor.
The second part of my job is to develop solutions, apps, tools. These are really only developed when a vendor fails so badly that they have no choice to let me do it. The stuff I develop is fine tuned for what our company needs, is often integrated with employee info and other sites, and is much more well received (management fully acknowledges this) than vendor sites/tools.
So we have all of these vendors getting paid somewhere between 50K-2.5M a year. Management knows that I can duplicate most of the work myself, or with a small team. But every time we talk about a new project and someone brings up that I should do it I hear, "And what do we do if XXX leaves?"
How can I address this with my management? Because of this I spend countless hours on vendor calls. For some projects I could have finished the project 4 times if I had the vendor call times to do the work.
Note: This question might be mildly related to How can I prepare for getting hit by a bus? but it isn't the same thing. I am not worried about getting people ready for my departure. I want to know how to convey to management that they could hire someone to take over, how to show them how much money/time/technology edge they are losing with their strategy, and ideas on what others have done to create a structure like this before.
Addendum: It is my opinion that upper management generally likes to pay vendors tons of money. I hear our VPs mention all the time that they manage a 3 million dollar budget or even mention vendors or whatever. To me having a small group in the company de-emphasizes the "power" or "work" of the individual VPs that own the vendor budget (even though they literally do nothing with the vendors). To me getting over this hurdle almost seems impossible. I jumped this 10 years ago for a few projects because my manager at the time got to highlight a new worker and took recognition. Now that people in my company know me, my current management would get little to no recognition.