I doubt those 14% are that confident. Confident makes it sound like it is a sure thing. I think it is more like: If they could, they would.
And it does not have to be a better job, it could be even one that pays less. If the person needed cash fast, this is one way of getting it. They could spread those losses over a year. It's still better than a payday loan.
Why better as opposed to one that is just as good? If you got another job that's just as good that'd be akin to getting a 3 months paid vacation. I would LOVE that
The ones that are confident they could land another better job by the quit date.
It's not enough to be possible to get any job. The offer only makes sense if you are certain you will trade up.