I wouldn't say only beginners want to get rich quick through gambling, because as far as I know majority of people would prefer a short cut to riches. I have seen an experienced gambler that lost focus and started gambling to make profit because he couldn't let go of his losses. Addiction is for both old and new if they don't caution themselves when gambling and gamble responsible.
I have a proverb for what you said: "A shortcut is a wrong cut." This phrase speaks for itself and tells us a lot of things. Apply it to gambling, if someone wants to be a rich person in society, they may turn to gambling. In some cases, I have seen many people with a successful record in gambling, but as beginners, those who enter gambling often become greedy and make mistakes, leading them to lose their winnings and ultimately fail. The rule is the same, when you earn a lot of money quickly by making just one mistake, your entire fortune can disappear at the same speed. This situation can later lead to addiction because they experience loss, then gain, then loss again, and they will try to recover their money, etc. Unintentionally, they will fall into addiction..