Not once have I had to have the transfer cases serviced.

Theres a difference between never having them serviced, and never
HAVING to have them serviced. They need fluid changes as well, even if
you arent using them.

So no, they don't cost any more for repairs.

You are waaaaay wrong here. What a mis-informed statement. If it
says 4WD..OR Marine...it always costs more.