This is a great post for validating management concerns about pulling in sexy new technologies for the hell of it. Every place I've worked I've been unable to convince management to use e.g. Rails (5 years ago) or node.js (recently). Even though I love these technologies and wish I'd had more time in full-time employment to learn and play with them, I understand and appreciate the risks implicit with adopting a shiny new technology in your company's IT dev/production environments.
It's also a great post illuminating how in hindsight some things can be really obvious (that building a high capacity web service dependent on a single-threaded server will give you problems down the road), but at the time it's not always easy seeing the woods for the trees.
For me though, the big takeaway was that one line summary: "You’re comparing a lower level server to a full stack web framework." Node.js has a pretty nice library/module ecosystem now, but for a complete full-stack solution with maximum productivity I would venture that there is nothing out there that compares to Rails currently.