Same Route, Same Time - Different Flight Path

I am curious.
Two different airlines, flying the same route, at similar times, with similar aircraft, but have two very different flight paths. Why is this?

This is not a one-off. I have been monitoring this for a while, and it is very consistent.
Two different airlines (South African SAA & Latam Brasil) fly SAA 222/SA 223 and TAM 8059/ TAM 8058 between Sao Paulo and Johannesburg (return) on a daily basis.
They operate similar aircraft (A330/A359) and depart/arrive at similar times.

However, their flight paths appear to be very different. One would expect the aircraft to “almost be in the wake” of each other - this is not the case. They take very different trajectories in and out of the two airports.
I am wondering why this would be. SAA always follows it’s path, while LATAM always follows it’s. Yet they are nowhere near to close to each other.
Why?

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