[rhet0rica]

The "when" isn't a mystery or gradual in the slightest—we have concrete dates.

The death of the button occurred on October 21, 2010, when Microsoft released Windows Phone 7 to the international market, beginning the Metro UI era.

Apple wouldn't catch up until September 17, 2014, when they unveiled iOS 7, ditching Steve Jobs's beloved skeuomorphism in favor of Jony Ive's signature flat style.

Google followed up on November 12, 2014, with Android 5.0 Lollipop's introduction of Material Design—arguably the least flat of the three, though it wouldn't stay that way forever.

[hedora]

Windows Phone 8 was pretty much only buttons in a grid, or lists of relevant information (with support for clearly marked hyperlinks). It was glorious.

They got rid of the button shadows, had them cycle through previews sometimes, and called them 'tiles', but they acted as buttons.

[mat_jack1]

I agree! I remember that we used to joke that at last we didn't need designers to do designs anymore. Colored rectangles were enough for everything!

Which I think was the reason that Microsoft did it that way and Apple tried to resist a bit. But the developer push was substantial.

[m463]

ios7 started a bunch of other nonsense, like hidden buttons, and un-link-like-links