While a lot of people take the creature comforts offered by civilization for granted, I'd say that as long as they leave society already armed with basic survival skills, it would be fairly easy for them to adjust to the wilderness.
The only thing that would really concern me is lack of quick and easy access to modern medicine. Say you're foraging for food and you trip over a tree branch and break your ankle. What then?
While Chris Knight certainly had basic survival skills, he was definitely not self-sufficient, going on a theft mission for goods approximately once per week. Besides, being self-sufficient in the wild requires quite a lot of land to support a single human - it's not something that a lot of people can do at the same time.
That may be true for us. But for Chris Knight, the environment that he can use for self-sufficiency includes the surrounding human population and their food.
The only thing that would really concern me is lack of quick and easy access to modern medicine. Say you're foraging for food and you trip over a tree branch and break your ankle. What then?