Maybe a layer of oil and pollution. Try to clean the windshield with a small % of ammonia in water, and use the same or ethanol to clean wipers: it worked very well for me. By the way, I actually read about some OEM windshields really defective.
I think I figured it out. The previous owner likely applied something like Rainex, and the problem I'm seeing could be the residue. I'll look more into it and see if I can figure out how to clean everything off.
Your situation sounds exactly like mine. Right after I picked up the car I noticed many tiny pits/scratches on the windshield that were visible when the sun was low in the sky. To me it looked like the windshield had been sandblasted. My dealer agreed that the windshield was defective and it was replaced under warranty.When I drive to work in the morning or leave the office in the afternoon, it looks like my windshield is covered in dirt. However, the window is "clean". I've been using the windshield wipers + water and even hand wiped the windows, but in direct sunlight when the sun is low in the sky, it just looks like there is dirt everywhere! Has anyone had this problem? To me it's like some sort of windshield manufacturing defect because the "dirt" that I see seem to be actually in the glass itself. They are not scratched. I'm not sure what I should do short of replacing the entire windshield. I bought the car Pre-owned earlier this month. It is a 2013.