Let's be realistic, the battery is a prime example. My old Grand Cherokee I could replace the battery by opening the hood, disconnecting the leads, pulling out the battery, and dropping in a new one.
I now drive a 2009 e60 535 xdrive that belonged to my father. I just had to replace the battery- it cost nearly $500 (this was on Friday). Although the battery is harder to access, the real problem is the battery requires "programming" from the dealer. I have read this may or may not always be necessary, but personally I don't want to screw with the electrical system here. The final breakdown was roughly $250 for the battery, $150 for installation, and $80 for programming. $500!!!
In most other cars the owner can just drop in a new battery for $130 (usually with a free install from the auto parts store). So in the BMW not only are parts (and labor) more expensive, repairs more complicated due to design, and reliability generally worse, there are an increasing number of circumstances where special software is needed to work on the car. These programs usually cost thousands so it's not in the budget for a typical owner.
This is already been mentioned and suggested. If you can afford to maintain a German car, great you should consider it with a great car like the 2015 Accord. No one is debating that going back to the dealer is in fact costly and is probably the biggest deterrent for buying a German car. If you can afford and don't mind the trip to the dealer, it's a moot point.
Now doing everything yourself is a different. Going back to the battery, I've worked on an Acura RSX before and I will admit that it's a lot easier to work on it because everything is easily accessible vs. a German car but I wouldn't say it's a lot more difficult to do - so I have to remove a panel before getting to something but that's hardly a problem if you know how to use a screwdriver/wrench. As for the price of the battery, maybe the cost of a car battery for a Honda/Acura is $130. I got a battery from BMW for $190 (cheaper if you find a compatible one elsewhere). Yes it's more expensive but nothing to really complain about if you can afford a BMW. As for programming, you don't have to go back to BMW to do it, any competent or good indy can do it for you and that will run you $20-50 tops. So after everything is done, it's $130 for Honda vs. $240 BMW. More expensive? Yes but not extremely significant and again if you can afford the maintenance, it's not that bad when compared to the $500 that you paid to have it done.
As for the software, any OBD tool or software will do if you're looking to scan/erase codes and those can be an inexpensive tool. Now there are extreme cases where the software won't work and you HAVE to go back to the dealer but that would usually mean it's a serious problem with the car in which case you would go back to the dealer/garage regardless if it's BMW or Honda.
Yeah, that's what did me in with our last (as in final) BMW, X5 4.4i, real street hotrod, not a _bad_ SUV[-esque] car platform vehicle, even a decent tow capacity.
It got close to needing brakes - just pads (even though the dealer suggested a full rotor replacement**) - and when I researched the OEM pads I was a little surprised by the price, found some aftermarket that were a bit better (some of my "go to" brands for other vehicles) - *but* I found out that the ABS sensor required a reset/recal after disconnect (which was required to rotate the caliper to be able to install the pads), and that required a BMW specific tool.
For this discussion, let's forget about OEM. What would be your aftermarket go to brake pad manufacturer? I'm fairly confident that there would be a set for BMW that would be in the same ballpark. At the top of my head, whether the brake pad is from ATE ($50-60), Akebono ($80-100), prices for pads whether it be for BMW or Honda, it's going to be roughly the same. This is the same as the ABS wheel speed sensor. $30 for the sensor and no special BMW tool required. Any OBD scanner will work to reset/erase the code and it's not specific to German cars, Honda's need to do this as well.
Again, this is not to offend/argue with anyone. Everyone has a certain level of patience and tolerance when it comes to cars. All I want to show is that the cost/trouble of maintaining a German car is sometimes over exaggerated.