Freeze dried is not the same thing as dehydrated. Dehydrating foods is something easily done at home, though not all food items lend themselves to the process. It is an economical way of processing food for storage that complements canning and freezing, but is is not as durable as canning or freeze drying, in general.

Freeze dried food does not need to be rehydrated to consume, but it may not be as palatable. Freeze dried foods thus consumed will rehydrate using digestive fluids, so an appropriate increase in water may need to be considered.

I am still waiting for the government to allow us to irradiate foods en masse so that we can have shelf stable, fresh food that is fully hydrated fresher than foods preserved using any other method. I understand we already allow some foods to be irradiated. This topic came up a long time ago and I can't recall now where we left it. Rather than let all that Cobalt and Cesium we have presently just sitting around doing nothing, we could be sterilizing fresh foods and avoid the risk of another ecoli or salmonella outbreak in this country. Everyone is so concerned about the risk of consuming an induced isotope, they don't realize we are constantly exposed to ionizing radiation in many different forms. The level of isotopic induction in foods by irradiation is so low, you stand a greater lifetime cumulative risk of exposure just going to the dentist once a year.