I disagree. This isn't FedEx's core competency or a differentiator for them. They're also not at a scale where it could make sense to colocate or build their own DCs. Fiddling with low-level tech infra would just be a distraction.
Now, they might find that software is a differentiator for them, but that's different.
For a logistics company, the IT system is the differentiator. Reliably routing and tracking packages to maximize utilization of trucks and planes allows them to be cheaper and faster. That all depends on both hardware and software. So I'd definitely think that running their own systems should be a given.
Now, they might find that software is a differentiator for them, but that's different.