even with slight speed bump, they could have offered 16GB RAM build to order.
it is really embarrassing to use 2015 technology and call it Mid 2017 MBA. Do not mistake me, I like the MBA and ordered Mid 2017 1.8Ghz, 8GB and 512Gb. Was originally intend to buy Ref 2016 rMBP and decided against it because of the dongles (and do not have one device/hard drive with USB-C yet). so this Mid 2017 MBA serve me for another few years.
I think in the year 2015, apple really offered lots of products at $1299 price point. Similar specs MBA, MacBook, MBP for $1299, you choose based on your needs (rMB, MBA, rMBP -> 5W, 15W, 28W/35W CPU ->portability/battery life/performance). now it is all weird. To get 512GB you need to spend $1700 on rMBP.