That's the simple truth, addiction doesn't come one Day but it may start off gradually as a fun untill it becomes a strap. That is how every addicted Gambler once started untill it get worst. One thing people do is that they keep on doing same thing repeatedly and hoping for change where as there are no hope.
It always have become a gradual process for every gambler. Some may not notice it too early because that's how it goes for most of them.
But then, when they have realized that it's getting worse on their ends. That's when they have discovered themselves that it's too late and they're already addicted.
The signs were there but they are in denial of it and that's why it's too late for them to quit when they have figured out.