Because working for ][ was a part time job, the game even says as much. You're not useful enough to work full time as a new acolyte. The reason you advance in rank is because the inquisitor uses his influence, partly has a reward, but partially because it pays to have people loyal to you in high places, and because it gives the acolyte access to better training and resources.
Because spending weeks, if not months, travelling to a different world is something you do for a part time job.
Pity the income rules heavily implied the part time job.