It used to be just really new and inexperienced vendors that they had this issue with, but I'm seeing it more with very long time vendors.
I'm thinking maybe it isn't always the host's fault, but the director or whoever is in their ear telling them where to go and what to say.
I always got the idea there was a countdown clock that the host/vendor could see as to how much time the segment had left, and if so, that should be a big help for the vendors to know it is time to wind down.
But yes, leaving the 'stage' is seeming more and more awkward all the time and for some very experienced people.
I sometimes wonder in the quest to make Q2 have more live programming, if they have really stretched the behind the scenes crews thin and things just aren't running as smoothly as they did and should, till they hire and train more people, who are the ones that really make all this happen.