I've never owned a microwave, instead I air-fry everything. Pretty sure this is the same trick restaurants use, especially fast-food ones. Microwaves make soggy leftovers.
No way is it faster. I can heat a bowl of soup up in 1 minute in the microwave. The pot is barely heated up after 1 minute in the stove, much less the contents.
Maybe it depends on the equipment. My stove can heat soup much faster than my microwave. Not to mention in the microwave you have to constantly stir to make sure it’s not still cold in the middle, because a microwave doesn’t heat evenly.
My guess is that it is a difference in volume. While a microwave is very efficient at exciting water in food, the range top is putting out a _lot_ of heat based on a 220V (in US) electric source or natural gas source.
Microwaves work pretty well for saucy Chinese food, for example. (The alternate method is usually steaming, which is even soggier.)