This has been a common state of affair in many places for thousands of years. But here is the thing, you don't need to indoctrinate someone as an agnostic.
An interesting comparison is the effort to maintain belief in Santa Clause vs end it.
On the other hand, I think the history of humanity, which involves nearly universal belief in some flavor of divinity, is all-but-conclusive proof that your second point is incorrect. That doesn't mean the x-theists are right: just that religion is quite obviously the default state of humanity, and irreligion is the exception.
I suspect in 10,000 years looking though limited and relatively random records Santa could be considered a widely warshiped god even if effectively zero adults believe in him today. Private journals are solid evidence, writing on temple walls is not. A coworkers Rabbi growing up was an atheist.
If we are going by popularity either Atheism or Agnostic beliefs are probably the single most common specific beliefs. Religions come and go, shifting through time so a modern Mormon has little in common with a 5th century Christian sects.