Depends on the model, depends on the care. I have had M-B that are tanks. Of course, I never buy them new and they always go to a mechanic for a thorough inspection before purchase is finalized.
Yes, the MB vehicles from the 1980s and earlier were very well made cars.
Literally the best quality you could buy.
Especially the turbo diesel engines.
However, since 2002 ish they have become over engineered and extremely expensive to maintain.
This goes for Volvos too.
Absolute tanks back in the 1970s with the 240 four cylinder engine.
There are models still around today with 1 million miles.
I had a 1976. I used to call it the tank because it was green.
Today Volvos rank in the bottom five of reliability.
Don’t even get me started on Land Rover and Jaguar.
Cheers