The costs referred to are "transition costs" and will always be higher in the initial stages of any new program. Also, this cost is usually made higher by trying to imitate the processes of an older technology rather than designing to the advantages of the newer. In the earlier days of steel construction (about 20 years ago) attempt was made to design to the advantages of steel, however results were spotty. Customers wanted products exactly like those they they were used to. Thus the advantages of steel were largely lost. Example, the earlier designs used larger, heavier gauge steel joists, widely spaced. This made the structures appear more like the commercial ones than the more traditional wood houses, so builders had to move to the closer spaced, lighter joist structures.
In the same way, steel structures will have heating and cooling problems. If designed to the natural advantages of steel, there will be a natural thermal "break" in the structure, however if wood-based practices must be imitated, this break is lost and the conductive effects of steel come into place.
The following might serve this subject somewhat:
http://www.home-advice.biz/framing.html
http://www.s-t.com/daily/05-97/05-18-97/d02ho181.htm
http://www.steelcastlestructural.com/faqs/
http://www.toolbase.org/tertiaryT.asp?DocumentID=3590&CategoryID=1538
http://www.swcp.com/~teeter/SG5.PDF
Finally, I think we shouldn't overlook the advantages of "hybrid" type structures, taking advantage of the best features of steel, concrete and wood. We could use concrete as load bearing inner part of the outer walls, steel for all of the interior framing and supports, and wood for trim. and as result, optimize for the advantages of each - - but then maybe this is just a dream. The following is a small bit on concrete (and steel).
http://www.diynet.com/diy/home_building/article/0,2085,DIY_13953_2349343,00.html