Simple: local maximum. If getting off welfare and into work implies immediate income loss, you are incentivized to stay on welfare, even if working would eventually make you better off, with time. If you are more inclined to respond to short term than long term incentives, you are stuck in a local maximum.
But there's no guarantee working would eventually make you better off? You're just taking that as a given. If there aren't any real prospect for higher pay -- then the issue isn't just "getting off welfare".
Better welfare (say free college or other education/training) might make a difference, however.
Now I agree that it would be good if people worked (if they are able) -- but in and off itself that doesn't make them better off.
"The likelihood of leaving low pay decreases
dramatically as tenure in a low-paying job increases. Low-
wage employment could itself decrease future wage growth
if it causes workers to receive less training or skill
development, conveys a negative signal to future employers,
or provides access only or chiefly to weaker labor market
networks. Significant numbers of stagnant low-wage
earners could also be visible because of “sorting,” as those
individuals with lower employment opportunities remain low-
wage workers. The latter finding indicates that, not only is
earnings mobility a reality for a substantial number of initially low earners, but also there is continued poverty within a large subpopulation of workers."
In other words, it's not quite as simple as "work will always win".
Yes, there is no guarantee working would eventually make you better off. Odds are, however, you will work your way up the income ladder beyond what welfare will offer.
You ARE guaranteed an income cap if you choose the welfare route: you CANNOT make more than $X or they'll dock your benefits fast enough that the transition to work is a powerful disincentive to doing so.
