The basic configuration still ships with 8GB of RAM. 16GB is $200 extra. I had an 8GB MacBook Pro in 2013. It wasn't enough then, it's absolutely inadequate now.
If you're not running VM's or opening hundreds of tabs in Chrome it's perfectly fine for everyday tasks.
I'm using my 2016 MBP with 8 GB and have never had a problem except when trying to run multiple VM's.
So 8 GB doesn't seem unreasonable as a minimum. You can upgrade if you need the extra, but a large number of buyers don't need it and prefer a cheaper base price.
It isn't there to purchase, it's maxed out at a measly 16GB. Plenty of workloads are RAM-intensive, but people who need more RAM are forced to spend $500 for a slower Intel CPU and GPU.
I'm using my 2016 MBP with 8 GB and have never had a problem except when trying to run multiple VM's.
So 8 GB doesn't seem unreasonable as a minimum. You can upgrade if you need the extra, but a large number of buyers don't need it and prefer a cheaper base price.