This line of thinking is true to some degree, especially since many lottery winners aren't really used to handling that much money before, hence it becomes hard for them to control the urge to overspend because they think their huge money will not run out.

This is why it's important for huge jackpot winners to immediately get a financial advisor as soon as possible, in order to guide them where to spend their money and how to make it grow. If I ever win a huge sum of money from somewhere, I'd rather pay a financial advisor a couple thousand dollars for every consultation rather than blow out all my winnings in a span of a few years. I know I'm a frugal person, but I do know that when I have the urge to buy something, I will do it no matter the cost which completely counters my frugality.

Circling back to the original gist of this that the majority of lottery winners aren't really going broke after a few years, I believe that this is true right now since everyone can easily learn where to invest, how to save, and there's pretty much tons of options to save money. You also have these experienced financial advisers that turn to Youtube to make contents that will easily help you manage your money for free.

Also, I think it also helps that most lottery bettors are middle-aged or older, as they understand the importance of money and how hard it is to earn them. Make a Gen Z or a Gen Alpha a lottery winner, and you'll most probably see them overindulge in luxury stuff in order to brag in social media without thinking the long-term implications of their overspending.