Ask HN: Why does Amazon and Facebook stil have an early 2000s front end style?

There’s some kind of principle that there’s a tipping point where an application becomes too big to ever do a major UI refresh. There are just too many pieces, too much hardcoded design, too many special cases to ever sort out.

See also: the company formerly known as Twitter’s attempts to remove Twitter branding. And that’s much simpler than UI logic.

They might look garish like Craigslist, but they're mostly functional rather than focusing on some trendy aesthetic like the 'flat design' trend that has infected the whole web. They're actually timeless in the sense they don't need to conform to trends.

Can you explain what makes them early 2000s because back then they looked much different.

Do they?