It will be more reliable because of its simplicity, but it won't last longer if they're both maintained to a high standard. You can't really get around the fact that a much higher end car using more expensive materials, construction processes, etc. is going to wear better over time. All of the highest mileage cars in the world are old european cars- mostly Volvos and Mercedes.
It also depends on how you use it... a Porsche isn't as reliable in daily driving as a Honda, but the Honda could be destroyed immediately with hard driving on a race track, and you could do it everyday for years in the Porsche.
I drive an old VW and old Porsche that are both decades old, with high miles, and basically both in brand new shape still. They get used very hard- the VW is used for camping offroad and heavy towing, and I both daily commute and race the Porsche.
Not the OP but I will bet you my boring Honda will outlast your high end luxury German any day of the week.