Most likely their production capacity isn't that high. They can't supply more than they can physically make, and in my experience outsourcing production to other shops usually leads to a trade-off in terms of quality1000 still wouldn't be enough, I've seen sales with nearly that quantity that went just like this, too
Exactly. And in this case, this issue has nothing to do with quantity. It's a mad rush whether there is 100 or 1000. The only way it slows down is when it changes to out of stock and people stop trying.
As for mass production in outsourcing, this is spit on. Something will be sacrificed. What it is who knows.