A company that pays a worker more than the MRP L will lose money and suffer the consequences as consumers choose a competitor's less expensive product. So, in a competitive labor market, wages tend to gravitate to the value of a worker's labor. Our mere dislike of the low value of someone's labor does not increase that person's chances of getting a higher-wage job. The aging Marxist notion of worker exploitation by powerful capitalists has failed the test of basic economics. If a worker is not being paid as much as his labor is worth, he will seek out an employer who recognizes that higher value and is willing to pay for it.
Charity is one very good way to increase individual well-being in the short run.
In the long run, increasing the amount of capital available to laborers is the best way to increase their opportunities and their wages. Too often however, the local government is the people's worst enemy. For an excellent article exploring this theme and applying it to child labor, see Kathie Lee's Children , by William Anderson.