I do agree the markup on these cars is a bit ridiculous. However, I think what people aren't seeing here is the GT350R will match/beat a (997) 911 GT3 RS. That to me is pretty impressive considering the GT3 RS starts at $175k, and the GT350R "starts" at less than $63k. This is your classic American muscle/sports car vs. the European competition. Another example is the Z06 Corvette, which is extremely capable on the track, and is a bargain for the performance.
Sure you can get a nice C63S, E63, CLS63, or M3/4, M5/6, but they are luxobarges, and not track oriented at all. They're much better suited for daily driving, which is 99% of what you see. I had a CLS 63, and while it was fun at Watkins Glen with a cooled butt and A/C, it wouldn't hold a chance to the GT350R. Two different cars built for different purposes.