If Gambling was not introduced then many people have to do the hard work for earning money.
If gambling is never introduced then we just will not know gambling. There is gambling or not, we still have to work hard to earn money. Do you think the majority of the richest people in the world get their money from gambling? no, they do not even gamble at all, they work hard in their respective jobs.
Gambling is not a source of money and should not be treated because then you will be in a desire state of wining from every bets and which is not possible practically. Also you will not like to explore other opportunities of money making which exists as your focus will only be to earn from gambling.