Apparently the cost to use disposable packages, including disposing them after use, is lower than the cost of recycling for this particular chain. Most likely it is not really the cost of separating the containers into a separate bin or whatever, but the separate logistics train back to the manufacturer that costs more. The logistics to remove waste are there anyway, so if you can reuse that for packaging all the better.

While arguably the total costs including pollution are greater for disposable packaging, most of those costs are not borne by the corporation and so it makes sense (for the corporation) to skip using recyclable packaging unless there are other factors (for example, there are customers who will pay extra for the warm feeling of knowing they are helping to reduce waste).