The emphasis , as always, is on qualified PhD students. No promotion and tenure committee will reward mediocrity and as a logical consequence, will not hire mediocre students.
For the PhD student, after having spent 4 years toiling endlessly, the last thing he or she wants is just a job. Dont underestimate the importance of picking the right university. You have to like the place you go to with all your heart. Otherwise, you will be miserable for as long as you are there.
The list of current faculty at any school will give you some good idea if you will be hired there.
Certainly I did not mean to say that having a PhD degree is enough for getting a tenure position at B-school or a job at Wall st. firm. But I definitely meant to say that there will be more opportunity available for the PhDs.
I happened to meet some of the MBA graduates who graduated during the 90s. They told me that many of them had 4-6 job offers and even some had 10-12 (wow unbelievable but it was confirmed by others as well). I believe it was because of more jobs available during those days. If more PhDs are required in future, certainly PhD holders will take benefit of few supplies but again the candidate has to be competitive.