I don't buy the "different key" argument either. Does that mean if I play most of the melody to "Manic Depression" but do it in a different key that it's a different song? Transposition is not composition. Again, it comes down to the timing for me. Sure, chord progressions are finite and will overlap. When they overlap with the timing mirrored as well we have moved beyond coincidence.
"I happen to have perfect situational awareness, Lana. Which cannot be taught, by the way. Like a poet's ... mind for ... to make the perfect words." - Sterling Archer