I used Arch in 2010-2012 (when I was very new to Linux yet had no problem installing Arch thanks to the Wiki) and something broke a number of times (maybe like 3 times a year). It also felt surprisingly slower than Ubuntu despite using XFCE vs Gnome2.
I then switched to Ubuntu and then to Manjaro and had only one break (it just wouldn't boot, but I easily found instructions on how to fix that) in many years straight.
I don't say Arch is bad but to me it seems like it is rather far from perfect while Manjaro is the closest to perfect I have ever seen.
Needless to say I appreciate Arch exists and am very grateful for the amazing job they do. Obviously no Manjaro would exist without Arch in the first place. Arch Wiki deserves a separate mention as it is of great quality and often helps a lot no matter what actual distro are you tweaking (it helped me with Ubuntu).
Approx how many times have you observed this in practice over, say, the past 2~5 years?