Because the process is slow, energy-intensive and capital-intensive, and because the product cannot be shipped in cheap packaging.
- **Cycle time.** A freeze-drying cycle runs for many hours and sometimes for more than a day. A hot air tunnel measures the same job in hours. Throughput per unit of equipment is therefore much lower.
- **Energy.** The process freezes the product, holds a vacuum and supplies sublimation heat at the same time. All three are running for the whole cycle.
- **Capital.** Vacuum chambers, condensers and vacuum pumps are expensive, and the cost is spread over that low throughput.
- **Yield.** Both drying routes remove most of the water, so both need several kilograms of fresh fruit per kilogram of finished product. In freeze-drying that yield is multiplied by a much higher processing cost.
- **Packaging.** The porous structure is hygroscopic and brittle, so it needs a high-barrier pack, often with a controlled headspace and sometimes a desiccant. That is a functional requirement, not an upgrade.
- **Fragility losses.** Fines generated in handling and transport are a real cost, and they are the most common subject of a claim in this category.
None of this makes freeze-dried the wrong choice. It makes it the wrong choice for applications that air-dried product serves equally well.