Buy TIME. Econ cost is secondary to that because the sooner the Guilds pick up a new quest the sooner we get a burden.
Hence nominally(i.e. mainly in name).
Also Buddhism claims god-like entities do exist(which look awfully similar to Hinduism's but they do share origin areas), but are ultimately not relevant.
Anyways, the HK are not suffering a plague of monotheism.
They believe other gods exist, they just believe there is a definite and significant pantheon head that should be reflected on the secular level.
We dodged this particular event previously by shutting down religion as kingmakers. They advise, but they aren't supposed to call the shots except as yet another voting elector.
We do actually get something AN didn't mention: Faction Power.
Factions you do quests for in rapid succession rises in importance and offers more quests.
Part of the current problem is we're a little TOO happy with finishing the Guild quests after all, so after finishing one expensive guild quest we get another, we rush it and finish that early, getting more...
Under the current system it is more optimal to drag quests out until their last turn to meet them.
And also a somewhat mixed bag there because Islam didn't really HAVE the same kind of central religious authority, or much in the way of restrictions of priests being unable to hold political office. Thus the Prophet himself and his children were heavily involved in administration and warfare, which probably got interpreted all kinds of ways.
Our own religious model is most similar to the Taoists, where they had great influence in court, but always in an advisory role and really would prefer to get back to their alchemy and stargazing(hint hint, o Emperor, bigger observatory, more expensive reagents)