I don't know what you are looking at or where you get your info, but that's nowhere near the numbers that I'm used to dealing with. A few cars have 8% markup from cost to MSRP. most are between 10 to 15% and few more have 20 to 25%.
No car that I know of that stickers at $26K only has $2000 in markup. And then the employee pricing goes down from there.
I'm looking at the http://www.gmfamilyfirst.com/ website.
Here's an example:
4WD Trailblazer LS
MSRP $26,530
Employee price $24,084