I have always wondered this, as well, especially in relation to how much people earn. I don't see a lot of comments on this, so I figured I would jump in.
I used to spend about €20 a week, never more than €5 a bet. At the time, I didn't have any debt or vices and was making just €800 a month with about €200 left over after bills.
These days, I have a business and work as a consultant, making upwards of €10,000 a month with €3,000 disposable income. I gamble about €250 a week. It's a lot more, but comparatively, it's much less, and I think that's what matters. The problem is that these days I gamble like an idiot. I make stupid bets and play games with low RTPs. I don't have much time for poker, rarely do any sports bet, and spend too much on slots and roulette. In the past, I was so desperate not to lose a single penny that every wager was important and often went on poker games, blackjack, etc.,
That's not because I don't care anymore, though. I think it's more about time and patience, as I don't have much of either these days.