Moment.js is 16.7k. Moment.js plus locale data for every single locale in the world is 68k. There is no justifiable reason to ever load every single locale in the world at once except for a few extremely niche cases. Real world use cases typically need one locale at a time, occasionally two or three, never hundreds.

Luxon, I believe, is a similar story.

The whole reason I use a date formatting library is so that I can localize dates into whatever locale the user is on. I can't just assume one locale and only load that.