Submitted via Google Form:
How can a world have no major religions but a vast number of small ones. Like no religion accounts for more than 1% of the entire population except maybe atheist for maybe 5% of the population? But what does that say about the distribution of culture/countries?
Tex: Major religions are often major because they are state-backed - i.e., they have lots of money at their disposal, so they become economically and thus culturally relevant. Religion answers, approximately, two major questions: 1) Are we alone in X or Y manner? and 2) I’m scared of X thing that I have difficulty understanding, what is Y solution?
For a place like Earth, the planet that we know the most about, there are no planet-wide confirmations about the physical existence of any deity in particular (as in, shows up in a grocery and says hello to you in an entirely unambiguous manner that all onlookers can agree upon). This means that religions on Earth are predicated on the idea that belief - and, thus, willpower - makes the deity real. Or at least “proves” it. Your mileage may vary.
Because of this, the real-world religions that you can observe and study will have many, many commonalities to the two general questions I stated above. The first question usually contains subjects such as sentience, and the emotional frills of that. The second question usually contains subjects such as death and the process of dying.
In order to have many distinct religions, you would need a lot of unanswered questions for various societies to answer, a severe lack of contact and communication between groups of societies, and most importantly a lack of (or lack of need of) money. The more travel there is, the more people of different backgrounds will talk to each other, and the more ideas will be confronted, shared, and discussed. Trade would correspondingly be low, because of the lack of travel.
Utuabzu: There’s a couple things to consider here. Firstly, how are we defining religion? This isn’t a trick question, it’s a genuine issue. The Abrahamic concept of religion doesn’t really carry over well to other spiritual traditions. Most other belief systems are more local and action-focused (orthoprax, concerned with what one does, rather than what one believes), and often lack any mandatory set of beliefs, or standardised mythology. Religions like Chinese Folk Religion, Shintō, Hinduism*, etc. can have wildly varying pantheons and myths depending on where you are and who you ask. So depending on your definition every tiny village could have its own religion, because it has its own version of the cultural mythos and its own pantheon including some distinctive local gods and dropping some more common cultural ones.
Universal (applicable to everyone regardless of origin or location), proselytising (actively attempting to convert people) religions are rare. There’s only actually a few of them. Most notably, Christianity and Islam. They are both also orthodox religions (concerned with believing the correct things), which means they have a standard mythology and theology (or several competing standards that have historically attempted to resolve their differences via murder). A third, very notable difference they have with most belief systems is that they are exclusive, you can’t (or at least you’re not supposed to) combine them with other belief systems. Most non-Abrahamic belief systems are more or less fine with syncretism (combining belief systems), most clearly seen with the way Buddhism** is practiced concurrently with folk religions across Asia.
So, in answer to the actual question, your best bet here is to just not have an equivalent to Christianity or Islam. I suggest reading up on non-Abrahamic and pre-Christian/Muslim religions and religious practices, as that should give you an idea of what such a world might look like. I’d expect it to be colourful and diverse, with cities filled with temples and shrines to an ever-expanding array of deities and hosting various festivals much of the year. Many people would likely layer a philosophy like Daoism or Stoicism over their day-to-day religious practice, and it would be common and expected for people to show respect to or make offerings to local deities when traveling. Religion would be a thing you do, not what you believe.
*Hinduism is less a religion and more a family of closely related religions and spiritual traditions that all originate on the Indian subcontinent. Which is why the Indian government considers Jains and Buddhists to be Hindu.
**Buddhism can be described as a religion or as a philosophy, depending on who you ask, what the context is, and whether Mercury is in Gatorade. Western definitions don’t really apply cleanly to non-Western contexts.