Why a PhD?

The more I read Dr. Rodney Decker's blog, the more I find I have in common with him.  I was surprised to find that he taught at Calvary Bible College in the early 90s (my undergraduate institution), did not pursue a Ph.D. at a 'prestigious' university, and yet he has proved that good scholarship makes a difference without regard to the location of one's doctoral work.  He has contributed to D.A. Carson's Studies in Biblical Greek series of scholarly monographs, Temporal Deixis of the Greek Verb in the Gospel of Mark with Reference to Verbal Aspect produced a Koine Greek Reader: Selections from the New Testament, Septuagint, and Early Christian Writers,  and has a forthcoming work on Mark and Biblical Greek.  Further, Dr. Decker has a helpful website and blog.  (Read more about him here.)

I mention this because I have personally struggled with what I am to do in regard to further education.  Ph.D.?  If so, where?  MBTS?  St. Andrews?  How big a megaphone will a degree give me?  Or must I attempt to develop a sphere of influence?  Where does this drive to influence others come from?  Is it from God, self, or worse?  These are some of the questions I feel I must answer.

Regardless, I know others are in the same boat I am, especially in light of a couple of relatively popular posts on religious Ph.D. studies: "Thinking About a Ph.D.?" and "Interested in a NT Ph.D.?".  Why not just be concerned about the faithful study and exposition of the Word of Truth (2 Tim 2.15)?  Perhaps part of being an 'approved workman' (for some) entails the rigor of research done on the Ph.D. level, regardless of institution.  Dr. Tomlinson at MBTS, KC,  and Dr. Decker at Baptist Bible College, PA seem to be two examples of professors who are involved in local church ministry while excelling in NT scholarship, though they did not receive their respective Ph.D.'s from traditionally 'prestigious' institutions.