On top of that, I always loved that standard GUI elements like buttons and text fields came with batteries included: they could be navigated with keyboard only,

On top of that, I always loved that standard GUI elements like buttons and text fields came with batteries included: they could be navigated with keyboard only, they were easy to read for screen readers, they followed OS contrast settings for the vision impaired, and so forth. All of this required minimal or no effort at all on developer's side. Accessibility has dramatically gone downhill since then. Everyone's re-inventing the same thing in Electron, but rarely do they reach the usability of a standard dialog in Windows 2000. Dark Mode is particularly my pet peeve: as long as applications in that era referenced OS color constants instead of hard-coding color values, they automatically followed OS color scheme without any extra work. Nowadays companies put out press releases and blog posts and parade dark mode around as if it was an achievement.