When Microwaves first came out they were huge but with a tiny cooking area and they were not affordable, and were mostly in business kitchens and a few restaurants. I would love a freeze dryer but the cheapest I have seen is $1600 and they only have 4 small trays.
Not necessarily. Most backpacking is going to be down in areas close to fresh water sources and you’d be bringing a water filter.
Hiking/camping where you can’t easily find fresh water is quite risky.