it doesn't always have zero people in it, and at least half of the that time any two guilds attempt to do that they end up getting followed
try winning more than 95% of your guild spars and then you'll probably see more of a need for a streaking system, it'd be nice to finally be able to spar until you actually lose

claiming that it'd assist in boosting makes close to no sense, the entire point of a streak is being able to continue until you lose
with the way it is right now you can just dodge people in the queue on purpose or even ACCIDENTALLY "boost" by being repeatedly matched with the random guild of 2 noobs that happens to queue at the same time as you
nobody wants to be forced to spar that every time

but again, the overall outcome of GS scores and anything in the grand scheme of GSing won't be changed much regardless of what changes are or aren't implemented, so it's not too big of a deal either way

BTW, come to the GS arenas if you are reading this thread and you don't already, they are really active lately