There is a huge difference between quitting because you have decided to do so and quitting because you're forced to, it is true that addiction cannot be sustained for long regardless of the amount of money that you have because at some point your money is going to run out, however a person that is still addicted to something will spend whatever money they get into their favorite addiction as soon as they get it, so even if they are not spending as much money or time as before they are still addicted because they cannot control themselves, so they still need help in order to overcome their addiction, otherwise they're never going to improve and leave that addiction behind for good.
Between quitting and what? I think you missed some words in your post, making me to not really understand what you are comparing with but if we are attached into something else, we are the only one that can fix it even if we say that there are other people that are concern and will help us because the final decision or act will still depend on us.
If the addicted person has run out of money then it's possible for them to do stealing with their partner of families money but if they can't get anything then they will do other crimes outside. This is why being addicted is bad and should be treated as soon as possible before it gets worse.