my wife, who is an astrophysicist, tells me that everybody in her fields uses this! one of the few things that unites different generations in astro

You know it's old when you see <frame> tags. A good look at JavaScript from 90s. What's really surprising is the entire body of the page is built in JavaScript - that's almost a modern concept when it comes to client side rendered apps.

Consider how little was wasted. There’s no build process, no framework, no plugins, no server process, nevertheless not only does it still work correctly and load instantly, it probably will forever.

As long as JavaScript is enabled. The tide is turning again towards server side rendering and JavaScript only where needed for interactivity.