It's an empirical question with a political implication.
Empirical because we would like to see data that bear out or refute Doug's thesis. As I discussed, the first post-reform data are not inconsistent with the thesis, but more needs to be said to determine whether his scenario is in fact playing out on a significant scale.
It's a political issue because the fact that Medicaid eligibility is not narrower, but broader, means that people can be organized to enroll. Their legal right to so already exists. State procedures to discourage this can be smashed.
This is in fact precisely what happened between 1968 and 1972, as the welfare rights movement organized the poor to reject associations of welfare with stigma and demand that their *existing* right to enroll in AFDC be recognized. This was the basis for an important movement, and if state governments are stupid enough to persist in blocking enrollment, it can and should be again. The 'enrollment' movement (for which "Regulating the Poor" by Cloward and Piven was the roadmap) had the great effect of overloading state budgets, which lead to greater federalization and growth of anti-poverty spending throughout most of the 1970's.
Another reason why, from a radical perspective, it pays to distinguish between rhetoric ("welfare is gone") and reality.
mbs