As far as I can tell, 1x setups became popular on MTB, then bled into gravel bikes. Reasons I've heard for this are that there are several nearly identical gear ratios with a 2x or 3x (I don't agree, the same ratio using a granny gear feels quite a bit different from the same gear using the middle ring; way more torque from the smaller ring)
The other is that the 'standard' FD is a poor design. I've found this to be true, especially as on many models the mechanism is very narrow and can visibly flex while shifting.
Finally, chain rub and triathlon gearing. I've replaced campy FD's on a very experienced cyclists bike because they didn't know how to trim the FD (which is easier on campy that Shimano imho). I've also had many triathletes bring their bikes in with broken chains and mangled derailleurs from cross chaining (using the biggest and smallest cogs at the same time.
There were double FDs that pushed the chain at an angle, I'm not sure what year, but I've seen 105 and rsx100 made like this. They work beautifully.
So poor(ish) design and rider error is killing multiple chain wheels.