Because dealerships go by a book which lists various problems along with the time it takes to fix them. The salesman at the service desk is a salesman and doesn't know exactly what's wrong or how to fix things, they just look at a chart. Not sure if you've ever tried to run a car dealership but I'd guess it's pretty expensive to pay the utilities, mortgage, and maintenance, pay taxes, and hire and retain competent help.
Getting rare import or brand new model cars is also setting yourself up to be gouged in price as there's no aftermarket solutions and not a lot of people who know what they're doing. My brother bought the Ram 3500 this year and is getting bent over the barrel for simple stuff like filters, breaks, and just general maintenance stuff since everything is too new for anybody except GM to be selling compatible parts. Lastly BMW hasn't ever been known to be a cheap to maintain car. It's like owning a boat or a horse, you should know getting into it that everything to do with ownership is going to be luxury priced.
A friend of mine works in the service department at a Ford dealership in central Florida (Horse country, not rich old New Yorker country) and their shop rate is over 180$ per hour. Shop rates are very regional specific I think.
