Here's the thing, by the time more then 8GB of DDR3 RAM will be worth considering, at least for gaming, DDR4 will be taking over. You aren't future-proofing your system by buying more older RAM then you actually need now when newer better RAM is right around the corner.
I'd bet most of the people who insist on 16+GB DDR3 today are going to be DDR4 early adopters. What was the point then eh?
Because they need 16GB today? You might not need that much, but that doesn't mean nobody does. Believe it or not some people use their computers for more than games and porn. And why would you assume people who have 16GB are going to be early adopters of DDR4? They'll probably switch when it makes sense to upgrade, not just because a new technology is out.
I'm perfectly happy with sitting on 8GB's for now. More then that for the vast majority of PC users is just completely wasted or at best so rarely utilized it still isn't worth the money that could be put towards a better GPU or something.
If you have completely disposable income though, I guess you may as well.. dispose of it. *shrug*
Again, it's like you're assuming everyone has the same exact usage requirements of their computers as you. You're not a power user. Some people are.
I said "at least for gaming" and "for the vast majority of PC users"
Translation: I didn't say everyone. My post wasn't directed at literally everyone. I'm aware there are other things that do benefit from more memory, namely heavy graphics processing in programs like photoshop.