I haven't looked at Pages 1-3 of this thread, so if I'm entirely missing the point, or if I'm repeating the argument of someone else who entirely missed the point (and who was subsequently chastised for his ignorance), that could (emphasize: could) be the reason:
Let's forget about fairness. Let's concede that there's no perfectly FAIR way to run a playoff -- this one, or any other one. Someone has to go first; someone has to go last. There's some unfairness there -- though, of course, we won't know till later who got the unfair end of the deal.
Let's go further than that. Let's say we don't give a rat's behind about fairness. That's not one of our goals.
So, now, having dispensed with fairness: How about excitement, drama, theater -- any word like that?
For the purpose of creating those things -- which, unlike fairness, I DO think we want: There can't be any doubt, can there, that a single group of playoffers would have achieved that objective better than multiple groups?
They should all have gone off together.