The whole question is what attracted a person to gambling - the desire to earn money or the desire to have fun. If the former, then the probability of addiction is very high, because the beginner will try to earn something (and then it often turns into an unrestrained desire to win back). If the latter, it is easier. It is enough to offer an equivalent substitute in terms of emotions and andrenaline
I agree that if someone approach gambling to make money they have higher probability of getting addicted than someone who approaches it for fun
it's not given, because there's a lot of variability from human to human
but probably.
One interesting thing to think about is how casinos could make their games and engines less addicting though it goes completely against their interests.