Historically, religion has focused more on orthodoxy than orthopraxy. However, this attitude is part of why people are leaving traditional religions. Because religion insists that praxis (action) is reliant on doxis, the individual is left out of the discussion and forced to either surrender to a static idea or leave and find their own way. And yet, religions wonder what is driving people (especially the younger generations) away.
By elevating doxis over praxis, traditional religion offers little room for individual thought, reason, and intuition. The tyranny of doxis ends individual questioning and seeking, and thus stops the path to true spirituality at a dead end.
The solution is actually very simple: make praxis king and let doxis be a matter of the individual's thought.
Rudolf Steiner, the Christian mystic and founder of Anthroposophy (which provided me with these lovely fonts), realised this over a century ago. With his book The Philosophy of Freedom, he introduced a theory called ethical individualism, brilliantly explained here. However, it can be easily explained as such: ethical principles, although objective, are still relative to each situation.
This idea prioritises praxis over doxis. By emphasising the need for individual seeking, intuition, and reasoning, it shows that following the impulses of spirit is more important than submitting blindly to dogma.
Unless mainstream religions can allow adherents to develop individual thought, they'll see more and more people identify as 'spiritual but not religious'.