>* In other words, Django used to be picked because it was the hot new thing, but since then it's no longer hot or new, but since enough people adopted it, they wrote enough libraries for it to make it worth continuing to use on new projects.*

Yeah, in other words, it's now both mature and with a rich ecosystem. Just the ticket!

And I wouldn't even say that people went for it because it was "hot new" back in the day. People went for it because it solved their problems. Being in fashion was never it's strong point, Rails and Node/Express did far better with that.