SE has a long and storied history of being terrified of pet jobs. They either make them extremely niche or err on the side of nerfdom when attempting to balance them. I forget where I saw it - and someone please correct me if I'm wrong - but I read that they never intended to put any pet jobs in FFXIV at all, except that when they polled between 1.x and 2.0, the playerbase overwhelmingly desired SMN as a new job. The job was produced, had a very strong initial showing, but now they're afraid of overpowering the pet/master balance and so they allow the other DPS jobs to shine a little bit brighter than SMN.