Ah, you raise a few interesting points.
>>the concerns of the unemployed and underemployed have tended to be politically ignorable (due to lack of numbers, cultural shaming, the perception that unemployment is always temporary, etc.<<
This seems like it must be true, but I'm not sure it is upon further consideration. Politicians have spent a great deal of time and effort on issues that affect the poor (and the comparative "poor"). In the US, we have a substantial welfare system that includes housing subsidies, a variety of food subsidies, and a variety of medical care subsidies. I would add that benefits under each of these systems has been pushed through by both "liberal" and "conservative" governments. (Many European countries have had an even greater focus on policies that benefit the poor.)
But I would argue that the biggest gains those on the poor end of the spectrum have made over the last 30 years (and certainly over the last 200 years) has been driven by market forces, not political ones. The widespread decline of food prices has been due to private activity, in spite of government policy (see, e.g., various agricultural subsidies/tariffs that maintain above-market prices). The enormous decline in prices of finished goods, durable goods, electronics, and basically anything you’d put in your home, has similarly been driven by market forces. This leads to a tremendous decrease in suffering that is difficult to measure. [For example, cheap air conditioners, furniture and televisions make what would have been miserable conditions in 1950's New York into perfectly pleasant conditions today.] So, perhaps focusing on overall growth will produce greater benefits to the poor than simply focusing on symptoms of poverty.
>>Since I think we probably both care a lot about equality of opportunity...<<
Equality of opportunity is a terrifying outcome. Of course it sounds wonderful in theory, but how do we attain it? The novel Brave New World illustrates how this would have to be done: (1) prohibit natural births, instead hatching babies under laboratory conditions; and (2) raise and educate children en masse, in a (presumably) government-run institutions. Of course even this would result in slight differences in opportunity. Even if everyone shared the same DNA, it would be impossible to ensure each person had the same experiences during childhood (i.e. Billy gets bullied for some reason and never reaches his potential while Bobby doesn’t and attains success).
So, in this respect, I don’t believe that anyone wants true equality of opportunity. The question is, how close is close enough, and at what cost? Because, at a certain point, the only way to increase equality of opportunity is to decrease freedom. We’re currently at the point where the main freedoms we are losing relate to how much of our income we get to keep (i.e. increase tax revenue to provide subsidies/programs for the poor). Most people don’t have a huge problem with this.
But we’re already begin to sacrifice other freedoms, and this is only accelerating. If your kid is fat, he will have a decreased opportunity to succeed. So, we impose sin taxes on certain ingredients. The FDA bans trans-fats. New York City tries to impose size restrictions on sodas. All of these rules are meant to save us from ourselves, or in essence, to give those with less information or willpower a more-equal opportunity to succeed. The same logic applies to smoking or drinking, housing, schooling, etc.
I’m not sure I see a logical place to stop. If someone notices you drinking or smoking during pregnancy, should society step in? There is a chance the child will be negatively impacted. Of course, this means he won’t have the same opportunities as if you had not drunk or smoked during pregnancy. This means the child’s opportunities won’t be equal to others due to your choices. Should we supervise or jail you to ensure you don’t drink or smoke while pregnant? Even terminate the pregnancy if we discover you drank or smoked while pregnant?
Of course, the child of a successful 35-year old mother who drinks or smokes while pregnant may have far better opportunities than the child of a 15-year old mother with no education who doesn't drink or smoke. To what extent should or must society intervene in the latter case?
The converse case is even more terrifying. I didn’t have an equal opportunity of succeeding because I had a stay-at-home mom who taught me to read when I was 4. She taught me years of history and science outside of school, things my peers never learned after 20 years of schooling. I got to peer over the shoulder of friends and relatives who ran successful small businesses. There’s simply no way replicate or ensure that everyone has these experiences (outside of a Brave New World-esque regime). Should my parents therefore be prohibited from trying to give me an advantage over others?
It’s fascinating to me that America chose a revolution based on liberty near the time the French chose a revolution based on equality. 200 years later, the world is a far richer place due to the advances wrought under freedom. Certainly giving people as much opportunity as possible is a worthy goal, but I fear the consequences of what would be required to ensure true equality of opportunity. So then, perhaps we’re back again to the more worthy goal: eliminating suffering.