You are absolutely correct. If you are going to buy a car in this category the cost of routine maintenance is going to be about three times what it would be for a Honda or Toyota. If you know that going in and want the car then it's easier to accept. My dealer charged $850 for the 55,000 mile service. Called my local mechanic who had taken care of our other cars for years just to get a quote and the price he gave was - $850.
Some people are going to snort and object, but the maintenance on our Lincoln MKT is never more than $120. Maybe Lincolns (and Cadillacs) are not in the same category as Audi and BMW--have never really thought about it. But as we start to watch our $$ more closely with college tuition coming up in a couple of years, the maintenance issue with Audi gave be pause, and coupled with their dieselgate crap, caused me to reconsider if I want to own an Audi or any other Germn luxury brand again. For me, I could be just as happy in a domestic luxury (or perhaps Japanese luxury) vehicle, especially knowing that I will not be on the hook for an additional $1000-1500/year in routine maintenance fees.
My Audi salesman told me when I bought the car that the dealers do not make that much on sales, but they make lots of $$$ on maintenance and service.