It does get better, but not by waiting for time to pass. The improvement comes from the walking, and the walking is small and unremarkable.

What the research says

In a randomised trial of group cognitive behavioural therapy for generalised anxiety disorder, the improvements were still there at long term follow up, and the group format made the effort worth more per person. That is anxiety rather than anger, and people in trials get more structure than most of us have at home. What it supports is the plain point that gains from a practised skill can last.

Strength of evidence: one line of research. A single study, or a theoretical account.