> Yet that jurisprudence pertains to all aspects of life.

As does secular law. Is it feasible for everyone to become a lawyer? Because that's the analogue.

> to expect so little in the way of questioning and intellectual exercise from the people who follow its tenets.

But that's just not true. You would only assume that if you were not acquainted with the Islamic intellectual tradition. Rather most people simply do not put in the effort that's necessary to develop the rigor and depth required to join the discussion. That's more of a comment on average human nature.