You do realize these companies have posted blog posts explaining the benefits of them doing just what you say they don't do... PayPal's Mobile.de team blogged about rewriting their Java system in Node.js and how performance was improved and how much faster they can work.

Netflix has also blogged about similar experiences.

Walmart blogged about how they rewrote their site in Node.js and was able to handle traffic on Black Friday way better than with previous systems.

PayPal themselves wrote about rewriting the account dashboard in Node and how it improved things.

This isn't snake oil or a PR movement. These are real companies using Node.js to make their businesses better.

Uber talks about how their whole infrastructure is built on Node.js

IBM bought Strongloop, self proclaimed "The Node.js Company".