All three preservation techniques are practiced today as they have been since antiquity. It is not clear to me where food so preserved are likely to fall on the processed / ultra-processed spectrum...
Microwave meals go back to the 1950s. If anything the standard American diet was worse in the 1980s. The idea of "health food" was only starting to go mainstream.
Then why don't we pickle or ferment things anymore ? Ah right because it's not as profitable.
Listening to you guys it seems like Americans in the 80s were starving and we should praise microwave meals for saving us from extinction.