There was a posting made by someone who spent over $240.00 already in extra cartel coins. That alone, is equal to 16 new paid subs. I personally did not spend anywhere near that amount however, I did purchase some more coins for a bit of a gamble and fun on some bags. Between my paid subscription and my extra coins, I provided BW with about 3 accounts for the month. 2 of which would be considered new.
Just a couple examples here. But indeed, this is working just as they had planned. They are making money now hand over fist. I personally hope they continue to make money so the enjoyment this game brings to some continues.
No one, has said for anyone to purchase just cartel packs or underworld ones. There are other things you can purchase that do not include the gamble.
This is why gambling works. Ask anyone down the bookies they'll believe the win more than they lose, the reality is almost certainly the direct opposite.