It's a big if whether 32 players could show up. Last time, there were 23-24 players, something like that. Just enough for 3 brackets.
Really, it comes down to this. After 5 rounds and 32 players, there will be a single person, the winner of the top bracket, who has gone 5-0 on the day. A sixth round, while possible to break the winners using Victory Points, lacks that poetry.
But, if we had 64 players! Well, then we wouldn't have room. Using only 16 tables is somewhat nice too, as it doesn't take up the *entire* store.