As I understand, Ehrenreich merely describes what her life in a low wage position was without making any explict claim as to "what's wrong with this picture" or what the "proper" situation should be. The implicit argument is that for the "living wage" i.e. the pay that should cover the cost of living, although Ehrenreich does not specify whether that shoul dbe achived by raising th eth epay or providing affordable housing and transportation - the two major drains on the low wage earners.
With that in mind, "the other side" can consist of the following three demurers:
1. While Ehrenreich's description of her experience in low wage position is accurate, that does not lead to the conclusion that corporations like Wal Mart should be paying higher wages (assuming that wages are determined by the market). Rather, one should demand affordable housing and transportation, which is the responsibility of the government/private charity rather than that of a private employer.
2. While Ehrenreich's description of her experience in low wage positions is accurate, generalizing from that experience is quite misleading because her experience was atypical for the "average" person working in this type of job. Low wage earners often pool their resources (housing and transportation) to lower their expenses, which Ehrenreich did not as she explicitly states in her book. Given the cost saving measures that low wage earners usually take, the minimum wage is in fact a living wage. Implying that this wage does not meet some arbitrary high standards (such as Ehrenreich's insistence on lving and communiting alone) has no merits, because we can arbitrarily cite a standard (say, a five bedroom flat on the East Side) that is beyond most wage levels.
3. While Ehrenreich's description of her experience in low wage positions is accurate, and it is indeed difficult to make ends meet depending only on low wage earnings - using that to argue for a higher "living wage" misses the point because such low wages were never intendeded to be the main source of income. Instead, they are sources of supplementary income for people who otherwise would be exluded from the job market altogether (e.g. students or th elderly). Since those people already have a source of income (such as social security or parental support) - earning a few extra dollars working a low wage part time job actually makes them better off. If the employers were forced to pay higher wages, this extra income opportunity woul dbe greatly reduced or eliminated altogether.
I presonally think that #1 is quite convincing from the Left's point of view, because it is asking for a collective (build infrastructure) rather than individualistic (increase individual wages) solution.
Wojtek