Back in ~ 2003-2004 I was working for an American company that did exactly that. The story was simple, they outsourced all IT (a few thousands) to a well known tech company. The selling point? "The tech company has a lot of expertise and scale and we will benefit from that". The results? The tech company took all the good engineers, moved them to work in other areas for other clients and replaced them with entry level technicians. It took a few years to start feeling the pain of what they did and a few more years to start reversing the change. By that time the C level people already retired rich, even today, 20 years later, the IT in that company is a terrible shade of "great leaders" and very low engineering skills outsourcing left and right anything more complicated than basic project management.