While we've likely always had "Why would X lead to Y?" questions, it feels like we've had a lot of them lately. Here's a sample (the questions asked so far in October, some have been closed).
- Why would mass suicide be the only way to summon a god?
- Why would people living inside a nebula go into space?
- Why would sorcery require the use of both sexes to be performed?
- Why would somebody want to stop the four elements?
- Why would characters spend time answering imaginary questions to fictional hypotheticals?
- Why would boarding school be mandatory?
- Why would my carnivorous species condemn murder?
- Why would anyone light campfires in The Zone of Alienation
I believe the above question type is distinguishable from "How would X lead to Y?" questions — better known as High Concept Questions. Here are those so far this month:
- How would corporations come to be more powerful than governments?
- How would one make a lion mount for a fantasy world?
- How to make firearms rare while metal is still widely available.
- How would the transfer of mass from the Moon to Earth change the rotation, orbit and speed of the Moon and Earth?
- Jobs in an AI controlled world
- How would a nomadic society revolving around train travel work?
- The Consequences of a Tidally Locked Earth
- How would a world power create an artificial winter?
My Concern: "Why would X lead to Y?" questions are almost always too broad. They're similar to "How would X lead to Y?" questions in that they're asking us to develop a substantial portion of the OP's plot for them. My gut tells me (and my emotional reaction when reading most of them) that they're off-topic.
And here's the hard part: unless they are ONLY answered from the rules-of-your-world perspective. I.E., "what natural law on your world answers this question?" Therefore, the first question on the list could not be legitimately answered (ignoring the specifics of the question)...
because the god demands it
because the life energy of 100 healthy, mature adults between the ages of 25 and 45 is required to trigger the summoning spell based on the rules of magic and/or theology for your world
...because it identifies how a rule of the world could be used to accomplish the task. or (perhaps better for the OP)...
Your world could require the life energy of 100 healthy, mature adults between the ages of 25 and 45 to trigger the summoning spell/incantation/invocation
...which helps the OP establish the rules of his/her world.
Question: Should we...
(a) Add "Why would X lead to Y?" questions to the Catalog of Question Types as off-topic without specifying a desire for rules-of-my-world answers.
(b) Add "Why would X lead to Y?" questions to the Catalog of Question Types as off-topic in all cases.
(d) Persuant to Cort Ammon's answer: Add "Why would X lead to Y?" questions to the Catalog of Question Types as on-topic but susceptible to being unclear and likely to be closed: please use our Sandbox or Chat to clarify the question.
And for completeness...
(e) Ignore the situation entirely.
With the goal of inviting the Moderators to add a line to the Help Center to reference this common question type.