While this might be the case for many of us, there is definitely a group of people who like risk and uncertainty. If you don't look for it you go for a safe 9 to 5 job without any upside. Your salary is fixed and you won't make any big pay jumps. People in the finance industry work a lot based on bonuses, so their salary is uncertain too. Or people working in sales are paid by commissions. There is also a change your salary per month.
Although both gamblers and employees get uncertain income, at least employees don't have the risk of losing money or the worst possibility is that what they did doesn't get rewarded, so they will only experience a loss in time and energy. Whereas in gambling, apart from an uncertain income, every gambler will definitely face the risk of losing their money.
Both are really different when it comes to the purpose of making money, have a job and you are safe but you'll only make a specific amount while in gambling there's no limit of how much you can make if you are lucky.. we call this risking high for a high reward, that's what gamblers do.
Some people does not really focus on just one, they like to gamble, they work to earn and use their earning in gambling, they'll only stop working if they are already making a decent money in gambling consistently, which we are rarely see as mot of us are losing in gambling.