Sprint switches
People pay Sprint to use their network. Theyre called MVNO's
(Definition)--->>>
https://www.phonescoop.com/glossary/term.php?gid=113 »
The only thing i can think of, is that Sprint and Verizon roam off of ach others networks...hope it helps 🙂
Now, the fiber backhaul is a different story. There are parts of the fiber that is owned by other parties, but that is the same thing for them as well.