Any number here given without context is completely useless (other than for a small amount of entertainment). Regarding the $2.8m/need $3.2m (assuming USD), it's basically a given that their income is higher than 99% of the users of this forum. That said, relatively speaking, it's also possible that they could be on a similar ~10-15 year working path as most users on this forum, but will simply have much more money. The actual dollar amount is irrelevant.
Me for example - as long as I have basic shelter, internet access, food, and maybe $500/mo in "misc" income, I'm basically good. I value my free time more than I do working a job I don't care about so my threshold is very low in comparison to most. I also just enjoy doing my own thing, which is why I value autonomy over just about anything else. I think most here have the same itch else they would be planning for much larger 'staches.
Different people have different priorities. Some want to travel rather permanently or at least have the option (whether in a spartan manner or lavishly, who are we to judge), start businesses, give to charities, provide for their families/kids in other ways. Others have significant health issues that they don't want to leave up to chance for later in life. There's no way to know any of this from someone's "number to retire".