In fact, once you start to service your car, that's where the problems start. We are not paying enough for mechanics to pay attention or care. The cars are not always designed for serviceability, some things can simply never be put back together the way they were done in the factory. There are no shops, official or not, that will use the recommended by vendor procedures or swap out all the required parts when doing some work.
Modern Japanese cars seem to last quite fine with zero service (again beside oil changes, brakes, fluids and such) for 200K+ miles/15+ years, after which they are worth so little and work costs so much that donating to NPR is the only practical option.
I do change things that aren't difficult such as replacing a turn signal switch in the steering column. But I think the premium for a Toyota or Honda is definitely worth it- paying to reduce probability of having someone wrench on your vehicle, leaving it with a new problem for each one it resolved. Then just hope no one runs into you resulting in the same issue- wishful thinking in an era where everyone is looking down at a phone (which should result in reckless driving charges and jail time).
I suppose it's like expecting even halfway decent QA on software that you purchase. At every place I've worked there is not even a dedicated SQL DBA let alone a legitimate QA effort or team.
This is one of the things I loved about maintaining my diesel Mercedes. It was clear that thought and great care was put into fastener choice. (Most) Anything that needed to be removed for service was a permanent fastener. No push-through "Christmas tree" fasteners on parts that needed removing for service; it was a threaded insert and a screw. Where the parts needed a plastic fitting, it was a permanent/reusable expanding plastic fastener, not a push-in fitting.
Contrast that with the Honda that needed less service, but so many jobs involved doing the job and then also replacing the broken one-time or few-time use plastic fasteners (after trying to find and buy it). Similar with my older Jeeps and VWs.
MB seemed to design their car to be serviced for 500K km. Others seem to design it to be cheap and fast to assemble and pass the "initial quality survey" and maybe the length of the warranty period without too many defects.
Have you done any work on the interior of your MB? Were they similarly thoughtful in the way things were laid out?
Since we're already going off topic, I may as well add that one of my dreams is to someday acquire an old MB, maybe a W116/W126, or even an older W108, and convert it to an EV.
Many of the interior fasteners, even if push-to-assemble were curved bits of metal spring that snapped into an FRP "box" to hold things securely and rattle-free.
As an engineer, I couldn't help but marvel at the care that went into some of the design and service thinking.
That's not to say it was all peachy. Mercedes faces the same realities and tradeoffs that other companies face, and they need to assemble cars to hit a price point that people will pay, and people don't want to see fasteners in the interior, so they use some plastic-on-plastic or plastic-into-metal in some areas.
The worst engineering I saw was that that car was eventually killed by rust, caused in large part by poor factory prep and/or a poor understanding of the durability of the (then) new water-based, low environmental impact primer and paint system that plagued the whole W210 line in snow belts. Perfectly good car sent to the junkyard after only 216K miles and 18 years. What's the environmental impact of that? Could have easily gone another 150K+ miles. Pity.
On old MBs, dad has a 1959 220S cabriolet that he's restored (to nice driver condition, not a show car) after we found it in a barn in PA, a W123 he bought new, a diesel W210 that isn't all rusty (as it's a southern car), an R170, and an electric Smart. With all those cars, the electric Smart gets the most usage...
After that I vowed not to take my car to the dealer so I took it to a well reviewed independent shop. On the way home after a fluid change and radiator flush my engine temp shot up and I discovered they hadn't installed a radiator cap.
Since then I've found a really good local mechanic, but being that he's in demand, his prices are high and getting an appointment on my day off can be a problem. I still take my car to him at least once a year for service and to have him look things over but other than that I do my own basic service. I usually schedule a day with a few friends and we work on our cars together. It makes things more social and less of a chore.