Like everything, this goes in cycles. When the iPhone launched, its UI was touted as revolutionary; simple, discoverable, not the convoluted mess that a typical windows experience was. "lol lolyou have to click start to power off your computer" and the likes. You had the physical home button, or the three buttons on android. They were discoverable, you handed an old phone to your grandma and she could just try things and figure it out.
Nowadays everything has to be clean and minimalist. No scrollbar, no buttons, just gestures. Hand a modern smartphone to someone who never used one in their life and see how they struggle to ever leave the first app they open. What are the odds they discover one of the gestures?