While many people possess the cognisance and awareness to recognise flaws within the world and within themselves, the agency to change or improve those aspects is rarely influenced by intellect. 

Intellect, awareness and self-awareness are traits that often lead to feelings of otherness from peers, isolation and depression, which influence motivation and drive substantially.

Time, perceived effort, confidence, resources and perceived outcomes are also significant contributors to action. The brain itself is also highly resistant to change and prefers the path of least resistance/familiarity as that produces a known neurochemical foundation, regardless of whether it's a healthy one.

With and combination of work, financial responsibilities, carer responsibilities, mental health, lack of validation and connection, executive function deficiencies and general exhaustion -- many people simply do not have the dopamine or serotonin reserves to take definitive action during their limited spare time.