@Xenograg One scenario that isn’t explored: the State doesn’t use magic because it considers it anathema, and suppresses it or kills its practitioners. This would be in keeping with the real world’s response to “witches”, and is very like the Dark Sun D&D setting. See also X-Men and Dune for situations where potentially useful power is sanctioned by the state, largely because the threat is too great.
On the one hand, this line of argument seems reasonable.
On the other hand, so does Lrrr's line of argument, "Why does Ross, the largest friend, not simply eat the other five?"
There are LOTS of highly useful skills, and we can look at all sorts of different historical organizations (and/or lack thereof) for inspiration. Guilds, unions, mercenaries, etc ... lots of possibilities...
@Xenograg You could go the opposite way and have the Mage’s Guild become a powerful supranational organization that meddles in politics precisely so that states cannot do this or states can only do this if the mages let them, à la the Witcher books.
This addresses wizards in a fantasy medieval state TTRPG, but it appears to me that it applies equally well to psionic people in a scifi futuristic TTRPG.
@michaelgemar@nyrath I presume you are referring to the Human PsiCorp. Its reason for existence was discriminatory control due to fear rather than marshalling control for use.