For mountain biking the simplification is wonderful. Front derailleurs were always a pain in the butt. With wide range cassettes 1x is just the way to go. It also frees up the left side of the handlebar for the lever for a dropper seatpost, which is a game changer in bike handling.

I very much doubt that's true, as evidenced by cheaper bikes still sporting 3x chainrings. 1x is entirely about removing the front derailleur and all its associated complication. It's especially common in mountain bikes because they experience a lot more opportunity to break.

That's what the bike industry wants people to believe so they have motivation to buy upgrades. 3x cranks weren't dropping like flies for 99.9% of users.

Their MO is to always come up with what's going to be the latest new thing then use the media outlets to pump their idea to boost sales. Same thing is happening with the forced imposition of disc brakes on road bikes. Then it's going to be hookless rims that can only handle 75 psi max.

When I was racing last (cat 3) the cost was higher on road bikes! Don't know if it still is. It is still a preferable setup if you don't need the range of gearing if a double. Front derailleurs are are common point of failure and noise and you make it all go away. (with either the proper sort of front chainring or a clutched derailleur in the rear to make sure the chain stay son)

Drop weight and improve aero a bit too.