In SL, a block of land on the grid is known as a "sim". That's an abbreviation for the word "simulation" because the servers simulate some aspects of the real world, such as gravity and wind and so forth. Most of the simulation isn't accurate. For example, in the real world, we can't teleport or fly and we actually float in water, rather than sinking like a stone.
But the simulation is a pretty good representation of the real world when it comes to the economy. In SL, just like in RL, most jobs pay so little for the time required that they just aren't worth the effort. To get ahead, you need to an equity interest in something scalable.