Often times not all decisions are clearly concisely explained in a way that lower level people can understand. One of the reasons that senior leadership sometimes goes with third-party software to pin integrations around is to lessen the reliance on in-house knowledge. This is often not directly stated but it is the goal of some people in senior leadership they trust external organizations that they can partner with more than they trust their local talent. There can be many many reasons for this and it's usually not because they don't believe their people are talented.
Oftentimes leadership will have great admiration for the technical talent of their people but they also realize that talented people are not slaves and can choose to leave at any point. They mitigate this risk by using external utilities from vendors. It's very common for the top talented people to push back against this because it feels as if it's an attack on their abilities when in reality it's mostly a risk mitigation scheme.
All companies do this as they grow and change and you either grow and change with it or you move on. The option of moving on is exactly why companies choose the strategy you're describing. So it is a bit of a self-perpetuating cycle but it is what it is.