The first flip phone dates back to 1996 - the Motorola StarTAC - that's essentially the Jurassic Period of mobile phones. And at one point the hottest handset in the world was a flip phone (Motorola again with the RAZR V3). And now they are all but gone aside from the occasional featurephone with essentially 2004 hardware and the rare China-only flip smartphone. What happened? Well, we can tell you right now that the asteroid struck in 2007 - that year saw a precipitous drop in new flip models being introduced but also a major fall in consumer interest. Let's rewind. The "clamshell"...
Source: https://www.gsmarena.com/counterclockwise_flip_phones_rise_with_the_tide_then_sink-news-35240.php