In a nutshell - you have to do deliberate practice or you stagnate. Musicians know this for ages.
For example, a person that habitually blames everybody for their failings may undertake a project to write a blog post every day but may be incapable of hearing advice, critical opinions or diagnosing reasons behind non-existing or stagnating readership statistics. They might blame everybody of being stupid or have no taste or not knowing anything about writing.
Yes, there can be emotional ego barriers, which hinder seeing. "It's amazing what you can see by looking."
But I think there's also a genuine non-emotional, cognitive problem with seeing, for a non-expert. An expert coach would help... but how to evaluate expertise? Maybe credentials are enough, for a beginner.