it'll be because the online review site or the Best Buy tech guy told them about it.
I will reveal you a secret. There are many beginners who don't care about online reviews, or the shop seller. Especially those who comes from an visual arts background, and don't care at all about spec lists (unlike many from a tech background). Especially if they attend courses, they'll ask the teacher what camera they should buy within a given price bracket - and most good teacher won't ask them to overspend for features they're not going to use.
Otherwise, believe me, Fuji Instax cameras won't be so popular, for example.
Then, of course, there are the spec list collectors, and those who just want a camera and ask a shop seller - who will sell them whatever he/she needs to sell most that day, regardless of 4K or whatever else.