I dunno. For the vast majority of people, the 'under $100' bikes at the department stores fill the need plenty.
Ya ya, if you are going to be putting on 5,000 to 10,000 or more miles a year on a bike, then you deserve better. However, most bikes don't even roll 250 miles in their total lifetime.
I have seen plenty of the cheap bikes. Yup, they are heavy, and yup, I have seen some atrocious quality issues, but quality isn't that big of an issue for a bike that isn't going to be used much