Your analogy makes no sense. While 8GB makes sense for you, it might not make it for someone else.I know that, I don't have a problem grasping such things, which is why I don't put a 450 Hemi in my Ford Fiesta (for lack of a better comparison). In other words, if I really needed a computer with 16GB RAM I would get a 15" Pro or the like. I believe the 13" Air is intended as an on-the-go computer. I do not need to edit 4k video with 250 open browser tabs in a coffee shop.
If I had to buy into all this future proofing hype I would be regretting my 8. I am not. I am as happy as a pig in ***t with my choice, and it is already capable of way more than I need it to do right now. If you really need 16 RAM you should know it already and should not need to ask such questions. The fact that people ask means they are doubting, in which case I just say get the entry level machine and be done with it.
Oh, and who needs to put over 200GB of apps on a 13" entry level laptop? I'm genuinely curious.
And for the record, I have no problem with people buying specced out machines, it's their money. I only share my experience so those who think they may have similar needs can make an informed decision.
Also, 200GB of apps is what? 3 big ones? That's it? Remember, this is a portable computer. While it's nice to share experiences, I'd rather tend to focus on what the poster actually needs as it's their needs we have to address.