There are many ways of accomplishing this, of making sure there is a constant pool of cheap, unskilled labour. To shine your shoes, or wait at tables, to open doors or deliver pizzas.
One way is to criminalise behaviours used by the underclass to enjoy themselves. Not too much - just enough so they get a criminal record. Just enough so that few in the underclass have respect for the majesty of the law. Just enough so that doing time in jail is not seen as a big deal, it's something most everyone does at one time or another.
Enough to make sure that predators on the poor are indistinguishable from their prey - predators who will keep them from rising above their station, and stop them from saving. Because any savings will soon be stolen, and wasted.
Another way is to arrange any taxation and social security net so that there are positive financial penalties for being "uppity". That unless you earn more than the average wage, you're actually better off in monetary terms earning minimum wage, and not a cent more. Ideally, if you earn in-between minimum and average wage, you should be financially worse off than earning nothing at all.
Consider these figures for a family of four in Mississippi:
See what I mean?
Note that the actual disposable income of the lowest earners, after food, shelter, and healthcare are paid for, is less than $2 a day per person. For books, for additional education, for clothing, for telecommunications. For school outings, and savings for higher education costs. For Holidays.
Not exactly a life of ease and luxury, is it?
For those who are on an average wage, they actually get less in the way of raw monetary terms. The difference is though, that they have choices in the way the money they're benefiting from is disbursed, and that shouldn't be under-estimated. Not having to shop at places which accept food-stamps. Being able to have more choice over diet. Not being compelled to have their children served meals where "ketchup is a vegetable" at schools.
Not being reminded in a myriad of ways that they're the underclass.
No, I've not turned Lefty in my old age. Or if I have, it's because the Right has moved away from me, not me from it. I still despise the demagogues that "mobilise the vote", using a combination of racism and the politics of envy. Neither do I buy in to the idea that this is all the product of some vast, malign conspiracy. Like Topsy, I think it "just growed".
But from an outsider's viewpoint, any society where such a vast proportion of the population is in jail, or recently released from jail, that society has a problem, no matter what the cause.
It doesn't have to be like this. It's not like this in most places, though there are positive advantages for those living "in the middle" in the USA. Paying less for meals - because the kitchen staff are paid peanuts. Having a gaggle of servants and bellhops, where in other western societies, there's far more automation as those on the bottom are so much more expensive. Rents being cheap, as houses are cheap, because building labour is so cheap. Even in rural Australia, $4350 will pay for 6 months rent, not more. Less in most capitals.
Canberra House and Unit (Apartment) prices:
The houses aren't exactly mansions either.
From TheBlogProf, a graph showing relative tax burden :
This is always a bad sign. It means one of two things: either a welfare state out of control, doing a Robin Hood act. Robbing the Rich to feed the, well, not exactly poor, but the State Bureaucracy that paternalistically manages the poor (for their own good of course)... or it means that income inequality has become pathological. The place now has a 3rd world income demographic, a few obscenely rich oligarchical families owning and controlling the country's wealth - with the politicians owned in fee simple to maintain the status quo.
Both are perversions of the Free Market that has proven so successful in wealth generation in comparison with un-Free systems.
I'm good at diagnosis, but cure, that's another matter. That's up to the US voting public. The discontent has given rise to the "Tea Party", but that can easily be co-opted into expending its strength in unproductive directions. It's not certain that less regulation is the answer - because that will just give the oligarchs free rein to distort the market further. More regulation though is even more dangerous, as it allows the Big Players to raise barriers against entry, and to drive lesser ones to extinction by fixed costs, independent of revenue.
What's needed is for an investigation of what existing regulations have been flouted with impunity, by whom, and how. The Rangel case is a perfect example - the man in charge of the IRS (US Tax Department) cheating on his taxes with no criminal or financial penalty, other than having to give back some of what he stole.
When Laws are only to be obeyed by the Little People - then you have a problem. When you have businesses too big to fail, when you have the very, very wealthiest paying no taxes to speak of, shifting the burden onto the merely rich.. then the problem's bigger still.