The game MapleStory, which has been very popular these days, was analyzed for the map earning of @MaplestoryU. Earning 20 units per hour seems to be less than working in a factory. A friend tested a level 190 map and averaged 2.5 neso per monster. Calculating with the most efficient monster-killing Fire Poison Mage, killing 10 monsters per second, with 3600 seconds in an hour, the total income is 90,000 $neso. With 100,000 $neso exchanged for 1 $nxpc, it directly calculates that 1 $nxpc is roughly 20 units. It's important to note that this is already the top-level map and the highest monster-killing efficiency. Even so, it's still not as high as factory work wages, so it seems we can only rely on equipment drops from boss fights and other gains to make up for it.