I have been using Leica gear since the 1970s, as well as Nikon, Olympus, Pentax, Canon, Hasselblad, and a few others. I've had various and sundry cameras from all of them need service from time to time. Without being part of any professional association with any of the manufacturers, I have seen very very little different in terms of service turnaround for all of them. Leica USA, unlike any of the others, has done me a favor or two now and then (like grandfathering in a warranty service to my first X2 when the four-way controller got flakey two months past warranty...). Only two of my digital Leica cameras have ever required a service ... that X2 and the refurbished M10-R that had definitely been knocked or dropped when I bought it, throwing the rangefinder off.
Over the past 15 years, I've owned digital Leica cameras (various Ms, SL, CL, X2, etc), most bought with a spare OEM battery. Despite at least 50,000 exposures between them, I've never once had a bad battery or seen battery performance drop to the "must replace battery" point.
I think there is way too much entitlement going on with most of the complaints I see on these various camera forums. These are robust, durable cameras with very low percentage numbers showing problems requiring service or repair. I've had more issues with other camera brands, several cameras of which required more than one trip to service to have a problem taken care of. That's not happened with Leica cameras, for me anyway...
G