At the casino's though the chances of you winning are posted and known in advance. All of the modern slots are programmable by the owner as to how much "hold". On larger bet machines, the hold is a smaller percent, like 1-3%. From the consumer/user standpoint those machines have a 97-99% payback or a win rate of 0.97 - 0.99. Machines also have a different number of rounds to play before a jackpot is hit. A 1$ machine with 5 symbols and 5 columns that need to match, for one symbol would have ⅕ × ⅕ × ⅕ × ⅕ × ⅕ = 1/3125. But there are 5 values that can match, so win chances are 5/3125 or 1/625. If it paid off $625 every 625 rounds, the winning odds on that machine would be 1.00. Say the machine owner inputs their "hold", at 4%, that means in 625 rounds the machine only returns $600. For a gambler, they'd rate that machine having a 96% average return. The odds are supposedly better today, but 18 years ago, on Nickel slots, returns ranged from 93.4% at the highest casino, to 85.02% at the airport. Now days, some casinos advertise a 99% payout on some of their slots.
Think for a second, comparing slots with trove. w/slots you get back over 90%, average. With trove, the payback isn't in dollars, but in virtual goods that have a 0 dollar, incremental cost. In vegas, the main source of income is from slot machines! Even with casinos giving back 90% in real money, the slot machines are where casinos make most of the money.
Ignoring the value of the payout, one might look at the frequency of payout on highly wanted items. Well, if something doesn't come out in 2000 plays, its not
likely to have very high odds of being paid out. In all of this, whether NCSoft gives you a payout in 10 plays or 10,000 plays, their incremental cost is still $0.00.
Now you can claim that you should expect nothing from NCSoft's "prizes", but note, it also costs them nothing to give you a nice item vs. a fortune potion. So it's a bit one sided to say that players should expect nothing when the founder of NCSoft, is #1349 this year on Forbes richest people list and is #10 on the list of the worlds wealthiest video game billionaires.