There's no doubt that there is a price point around $10 that is very attractive in the wine industry.
However, Two Buck Chuck and it's ilk, many brands selling under $5 a bottle, proves that while price and quality may be somewhat correlated in the wine industry, quality is not the causation for price in all instances.
What the chart shows me is that most Americans drink wine as a table beverage or an indulgence, rather than as an oenophile's pursuit. That has historically been true as long as there has been wine in this country.
As a non-American: I'm always taken aback at how cheap you can buy alcohol.
The chart does, however, show a fair consolidation of brands under an umbrella organization. While not as bad as beer: I bet the top 10 organizations control >60% of the wine in the USA. And that's not good for anyone IMHO.
Having just completed Wine Wars by Mike Veseth, this chart confirms some of the data he presented in his book about the way that Constellation Brands and Gallo approach the "wine wall" marketing. I think the book is about 4 years old, but the trends he outlined still appear to be present. I started following his web site after the read as he keeps it updated with fresh information. I didn't know that Aldi owned Trader Joes (or should I say the family that owns Aldi), and their approach towards wine marketing was eye opening.