RE: "Let's talk about the other end of the oil problem.  Flowing in extremelycold weather. Does synthetic oil make more sense when the outside temperature is -40� F ?"

 
Absolutely!!  For your own comparison take one Coleman(or other) cooler, into it put Dry-ice, then add styrofoam cups filled with your favorite brand & weight motor oil, gear oil, atf, p/s fluid, etc, add thermometers and wait. When the temperature stabilizes compare the viscousity of the lubricants, for added fun take pencils and stick them into the fluid in each cup, then try to remove them.

One benefit to synthetics that I have not seen addressed yet is their abililty to adhere to engine parts better. Most engine wear is said to happen while starting, the superior adhesion of synthetic lubricants reduces this wear greatly.

Mark in AK  BTDT