I understand a grandma could have had a microwave. After all, I remember radar ranges with mechanical timers that were already relics when I was a child. But, now you've got me wondering what kind of VR/holographic microwaves kids are buying.
My latest bought a couple years ago still has a 7-segment vacuum fluorescent display. And a digital encoder knob and buttons rather than membrane controls. And a "cyclonic" inverter, which from the marketing diagrams, you would think can bend reality to your whims.
Those were the best. Dead simple to operate. That said I still have the Goldstar microwave I bought over 30 years ago, which has a keypad and digital timer.
One of my friends owns a normal-looking radar range kitchen oven. It can cooks with both the convection oven and the microwave at the same time. It is from the 1970s and has all mechanical dials. It has a metal rack inside and you can use any cookware, without a metal lid I guess.
I think maybe the original killer app for microwaves was baked potatoes? An hour to cook in a conventional oven. 5 minutes in a microwave. But maybe no one eats those anymore?
I haven't tried that, but my guess would be the same problem as most solids in a microwave - uneven heating / cold spots. That's why liquids and popcorn work so well, liquids mix themselves up and the unpopped kernels fall to the bottom of the bag.
I have one (800w) that takes about 5min to cook a potato (200gr), the manual suggests "once the potatoes are cooked, wrap them in tin foil for at least 5 minutes to cook through" but I just cook one wrapped with baking paper.
Technically popcorn is just warming up liquids as well. I'd say that's all it's good at, which happens to have a handful of usecases(some frozen meals, popcorn, melting cheese, heating leftovers).
