At the beginning of the film, we can see a small (barely noticeable) certificate for sailing and navigating at Chuck's home.
While the "death" of Wilson is very sad, in order for the main character to function normally in society, Wilson had to go.
The title itself, referring to the fact that the film is mostly Tom Hanks on his own, i.e. with the rest of the cast away.
Compare the scene where he climbs to the top of the island for the first time and grasps his situation with the final scene at the crossroads-360 degrees of isolation compared to the infinite pathways the crossroads represent. It's that contrast that hits him in that moment.
What if the last unopened package contained a waterproof satellite phone with heavy duty battery?
In the parody FedEx commercial, it was, along with a GPS, fishing rod, water purifier, and seeds. In an earlier version of the script, two bottles of Salsa Verde.
We see the hard work that goes into making rope for Chuck's raft—he pulls small saplings, strips the bark, weaves it together, etc.. Now picture him going through this painstaking process for the first time—all with the goal of making a noose to hang himself with!
The same coral reef that kept larger, more dangerous fish away from him also kept him from leaving the island, or being able to attract attention from passing ships.