There are many reasons why people prefer gambling from gaming. For me it's mostly the time required for each of these. If I gamble I spend an hour doing it and can move to something else. Online gaming requires a lot more time as RPG games are divided into quests and many of them can't be stopped until you reach a safe point. There are boss fights for which you assemble a team and need to reach the destination and win the battle (I played some wow in my time 
) I wish I had as much free time as 10 years ago.
You can gamble even just for few minutes and you are not obliged to finish what you started. The same goes for RPG or any online game but the longer you stay there, you'll become stronger. While in gambling, its opposite the longer you stay the higher risk you have. ) I wish I had as much free time as 10 years ago. This also can be a time related issue why some preferred to gamble instead of gaming.