The answer to 'why is my landscape lighting overgrown' is that your landscape lighting has likely become overgrown due to the natural growth of plants, shrubs, and trees around the lighting fixtures. Over time, the vegetation can expand and start to cover the lights, blocking the light output and creating an overgrown appearance.
This is a common issue that many homeowners face, especially if they don't regularly maintain and prune the landscaping around their lighting. The overgrowth can also be caused by a lack of proper plant selection and placement during the initial landscape design.