This is the most overlooked sign, and probably the most significant. When people manage anxiety successfully enough to continue functioning, they often interpret the management as evidence that the anxiety is under control. It is not. Management and resolution are fundamentally different outcomes.
Management means the anxiety continues to operate at roughly the same level, consuming the same resources, imposing the same constraints, requiring the same sustained effort to keep it from becoming visibly disruptive. The strategies are working. The anxiety is not improving.
If you have been coping with anxiety for more than a year, and the underlying pattern has not changed, the coping strategies are not fixing it. They are containing it. Therapy targets the mechanism that the coping strategies have been working around.