1. Some questions in this category aren't actually about forgetting the Pinyin system, but rather, Pinyin for specific characters, often because people speak dialects where the pronunciations of words and characters don't perfectly map to Pinyin in Mandarin, or at all. Fuzzy modes serve that population. (Of course, there are also commonly mispronounced characters and words.)
2. A lot of older people educated in 70s or earlier may have been taught some Pinyin, but never systematically. I know from talking to people that this is especially true in rural regions (well what can you do when the teachers don't know Pinyin). They simply never mastered Pinyin in the first place. A good part of this population didn't even go to high school, but even highly educated people in this camp can have a bit of trouble with Pinyin later, after relearning; I know a PhD born in the 60s fitting this bill, and he could still stutter on a character's Pinyin from time to time when typing.
The questions you found are very likely from this camp especially when they didn't have to type for decades until smartphones became prevalent.
Younger people from 80s and especially 90s onwards were taught Pinyin from first grade or even kindergarten before they were taught to recognize characters, then PCs and smartphones came along to reinforce the knowledge. It's pretty damn hard to forget that.
Again, of course there are "many"/"plenty" of any kind of people doing fringe stuff in a country of 1.4 billion, but presenting outliers as common or mainstream is misleading.
2. A lot of older people educated in 70s or earlier may have been taught some Pinyin, but never systematically. I know from talking to people that this is especially true in rural regions (well what can you do when the teachers don't know Pinyin). They simply never mastered Pinyin in the first place. A good part of this population didn't even go to high school, but even highly educated people in this camp can have a bit of trouble with Pinyin later, after relearning; I know a PhD born in the 60s fitting this bill, and he could still stutter on a character's Pinyin from time to time when typing.
The questions you found are very likely from this camp especially when they didn't have to type for decades until smartphones became prevalent.
Younger people from 80s and especially 90s onwards were taught Pinyin from first grade or even kindergarten before they were taught to recognize characters, then PCs and smartphones came along to reinforce the knowledge. It's pretty damn hard to forget that.
Again, of course there are "many"/"plenty" of any kind of people doing fringe stuff in a country of 1.4 billion, but presenting outliers as common or mainstream is misleading.