You are right in everything you have said there. However, just to add mine, I think financial desperation could also be the biggest reason why gamblers keep returning after deciding to leave gambling.
With their debts piled up due to gambling, some have already assumed that the best way to resolve their financial crisis is to become non-stop from gambling. For them, that's the only possible way that they can quickly regain what they have lost, that's probably one of the reasons why gamblers keep returning after so much losses and countless frustrations they feel when they are deeply at loss.
There cases do exist but I question how often they come across, because we tend to give this advice a lot. Only the most foolish people would believe that they can get out of debt by continuing to gamble. It is such that we consider this error very basic, and to know how to avoid digging your own grave should not be hard. There are ways to work on debts, but gambling is not a way through which this can happen. The question in the thread is why many gamblers return, and I would think it wants us to list reasons that apply to many individuals but it may not be so because there are many reasons given here. The one that you provide is valid but I don't think it really is the case for even like 1 percent of return gamblers.
In cases where the "I am done" was a result of the gambler wanting to take a break from gambling, I don't see them coming back as an issue. The only time this becomes an issue is when the "I am done" was a result of them wanting to be permanently away from gambling, but yet return after a few months or a few weeks of taking that BREAK.
I could say I am done simply because I have experienced so many losses and just want to take some time off gambling to clear my mind, and then return, probably after a few months. That doesn't mean this is because I am coming back because I couldn't take the losses, or because I feel I have more control over my gambler though it might be true. Taking some time off from gambling will make you see things differently compared to someone who just keeps gambling nonstop for months or years.
It may be so but you have to consider that people who just decide to take a break can also be people who should permanently walk away from gambling, there are many people who have sacrificed a lot for gambling already even if they don't see it. This means that this can be a problem for some of those people in the group that decide to take a small break too.