It's not correct to draw a correlation between color, and Scott's prices. However, you are correct in saying that he's holding it down.
It's more correct to say that color availability is a by-product of the pricing. Mostly Scott is very adept at sourcing overruns and cosmetic seconds of fabrics that are very desirable to the MYOG crowd. Although, that nature of these fabrics is what creates such a large disparity between the prices of these materials, and the lightest, newest, cutting edge fabrics.
Don't think you're being gouged for a half oz difference in sq yd weight by comparing Scott's 1.1oz(unfinished or uncoated) fabrics, to the lightest available ~1/2oz fabrics, because the companies offering these fabrics are shouldering much higher financial burdens "bringing them to market" in the first place.
5,000 yard minimums are nothing to sneeze at, especially when you consider that sub 1oz fabrics can cost 3-4+ times as much per yard to get produced.
That being said, I'm pretty much Scott's biggest fan. Any MYOGer without a lot of confidence in their skills, would be foolish not to proto with the calendered 1.1oz olive ripstop or heavier offerings from DIY-GearSupply (backwoods daydreamer).