It's good to have an exit plan when you walk into any job regardless of qualifications or experience.
As for their lack of success applying for jobs, it could be down to a number of things. I wouldn't necessarily accept that it's over-qualification and/or lack of real world experience unless they are being told this explicitly. People do use these two things as a ready excuse. I'm not saying that this is the case for your colleagues but the majority of people I have met throughout my career who struggle to get work, struggle for very good reasons unrelated to their ability.
This real world experience thing is interesting. Employers will be looking for academically minded people who understand time budgets, cost awareness and have an understanding that if you are trying to create things like a new chocolate bar recipe, you don't look at reactions which use Rhodium catalysts etc.
I have seen some large companies insist that you have at least one or two postdocs before they'll hire a PhD researcher so it's not a clear picture.
My advice to these colleagues would be to look at the job specs and work out which things they are missing. Then actively figure out how to acquire those things. It's probably not a good thing to wait until the end of your academic career to work these things out.