The visa refusal rate in most of the less developed countries is very high. There are 27 countries in the visa wavier program that don't require visas to come here. It would be interesting to learn what countries these visa overstayers come from and what kind of visas they were issued. I think there are far more than 11 million illegals in the US. The number is closer to 20 million.
Interesting point with the visa waiver program the I-94W visa is NONcovertable to any other class of visa. Only the I-94 is convertable to another status (ie marry us citizen, student, etc.)
The path to citizenship is 100% amnesty.