Hey IV,
They may well be able to survive in the wild, but if the snake has a very weak feed response (like some I've met that just walk up to the food and swallow, wouldn't strike at a food source to save themselves) it may lose a lot of condition before it changes hunting tactics from how it's used to obtaining food; that's my take on it anyway. If the snake lost significant condition, it's chances of a successful hunt (without receiving serious injury) would be significantly decreased.
It's not just obtaining food that can be a challenge for captive snakes - predator avoidance can be an issue too - I remember a captive release program of baby womas in SA happening a while back, where basically all the womas just turned into mulga food (kinda funny but I really shouldn't laugh!), quite possibly because the baby womas were de-sensitized to living in close proximity to other snakes!
Apologies guys that was a bit off topic; do continue