Do you know, I utterly missed where he said "500 users" until you pointed it out.
Okay, you are clearly correct.
And the figures you cite for Node.js aren't really all that far off from Java Servlets if you strip your JSP server down to the minimum (maybe 2x to 4x better than servlets, but maybe not. My JSP is at least 5 years old now.). So yeah, it's doable.
An optimist sees the glass as half full.
A pessimist sees the glass as half empty.
A realist drinks it no matter how much there is.