Earlier quoted context omitted.
A nice overview, but it feels like the dates are out. Flat design came in much later than the 90s .. Web 2.0 was all about curved corners and gradients .. flat design was introduced in 2010s.
Noooo. I was a desktop software developer in the 90s and the conversation definitely started then. Remember we are talking about desktop software not web development (and by the late 90s bevels were seen as archaic as “under maintenance” GIFs). To illustrate the timeline: Windows MSIs were often compared to Install Shield with regards to the difference between the newer flat design elements of Microsoft vs the older…
I see your point re. desktop UI elements, but I think 'flat design' became a zeitgeist term in the 2010s for the majority of creatives / graphic designers.