alt Hacker News1x11 is a fairly recent thing. Came out in the last ~8 years, really. I was hesitant about going 1x, but did on my gravel bike (1x12) and it's a nice way to cut complexity, weight, and improve maintainability. That's not to say the era of the front derailleur is over -- I think they've still got their place on road bikes.
Came out in 2012 with SRAM MB group (XX1). The main invention was the narrow-wide chainring, before that there was no any advantage in 1x as you still needed a chain retainer in the front in lieu of the front derailleur. So it's fairly recent but not 8 y.o. 1x12 is already 10 y.o.