This is a great point. And actually, I've got an aging MBP with only 8 gigs of RAM that I regularly use pretty heavily editing movie in Premier and images in Photoshop and Illustrator while laying page in InDesign (my Adobe workflow as an example, since Adobe CC is far and away the most RAM hungry suite of software I use). I was going to upgrade it to 16 gigs, but I upgraded the HDD to an SSD instead and now (between RAM compression, file caching, and swap) 8 gigs of RAM is working great.
Skip to 2:09 to see After Effects and Premiere benchmarks 16 vs 32 vs 64