Someone two miles away is moving in eleven days. She searches “storage units near me”, opens the top three, and starts comparing: what does a 10×10 cost, is it climate controlled, can she get in on a Sunday evening. Your listing has an old photo, no recent posts, and no answer to any of those questions.
The frustrating part is that your facility is the better one. Newer doors, better lighting, a gate that actually works, an office that answers the phone. None of that survives a comparison she makes in four minutes on her phone.
So she rents from the operator down the road, and because storage tenants stay for months or years, that is not one lost sale. It is a unit that stays occupied by someone else through the whole season, and a review that goes on their listing instead of yours.
Multiply that by the moves happening around you every week, and your occupancy chart never quite recovers — it just drifts, and you end up discounting rates to fix a visibility problem.