这是完全倒装结构.
our passion for doing things for ourselves 的结构为：
中心词（即被修饰词）+ 定语 + 状语.
our passion + for doing things + for ourselves
该句子的正常语序为：
Our passion for doing thing for ourselve is so great that we are becoming increasingly less dependent on specialized labour.
that 为连词（属于虚词）,不充当任何成分.