They never implied "en masse." But yes, for what it's worth, those that would use Rails 10 years ago are now increasingly using JS based frameworks, such as NodeJS with express and/or Next.js. In fact, many people who are in web dev these days only know JS/TypeScript, they know zero Ruby at all.

Or maybe: those people that were using Rails 10 years ago are still using Rails now and those people that entered the job market in the last 10 years are using JS frameworks. That would match more closely what I see.

Exactly, that's what I meant, I should've worded it better. I see no reason for most companies who are successful to move off of Rails, but then again, many big ones have over the years [0], including Twitch, Airbnb, Hulu, Coinbase, SoundCloud, and even Twitter.

[0] https://twitter.com/dhh/status/1701299614148919301/quotes

proof? (I like nim -- but I don't see a mass migration)

The point I'm making is that people leaving for nim is a HN thing to say that's unrepresentative of what's actually happening in the rest of the world.