Why sports anime almost always use Single Elimination?

As the title states. The one big flaw of this system when used in the story is that the hero team must win all its games to advance the story, one loss and it’s game over, time to prepare for the next season if even there is one, and there usually isn’t one. Also, the way they distribute seeds is oftentimes too unfair for the hero team (they’re usually the bottom seed, duh) yet the villain team (which is usually the top seed) cruises through the tournament final with only much fewer matches, like maybe 1-2 as opposed to 4-5