[dgdg]

Because of Bootstrap. Everyone uses it. Every old website that looked different in the past, now does a UI refresh (by just using Bootstrap out of the box with minimal customisation) and becomes another one of those the same looking websites.

[wild_preference]

Outside of the HN comment bubble, nobody uses Bootstrap. And it doesn't explain the examples in TFA.

[david-cako]

Speaking anecdotally, up to around 2016 every other website used Bootstrap or Foundation, often with minimal customization, just because it looks and works well out of the box on all devices. Now it seems like it's getting better, but generic UI components are an extremely relevant aspect.

Promethease is a good example. Years later a bootstrap website signals to me "it's about the functionality, not the design". https://promethease.com/

Before that everything was jQuery UI. Government websites still use a ton of it. All of Colorado's web portals are built with it. And now things are shifting towards UI frameworks "plus more", like Ionic, which adds a bunch of design/devops workflow and cross platform functionality.