simplify First, everyone with lots of side income, when losing their main job, will still have sources of income. This is because they have a wide array of income generating passive jobs that can mitigate or cover for the gap their main job would leave if they lost it. This is the principle of different types of income, which are earned, passive, and portfolio income. Earned income is the income we'll have in exchange for our valuable time. These work in wages and salary, where we need to be active to be able to earn. Passive income on the other hand, are income we generate even while we don't do the work involved in them. And lastly, portfolio income. These are the bonds, equities, investments, stocks that you have invested on. Most of the upper classes earn from passive and portfolio income. This is why it is important to have multiple sources of income. On the other hand, if people have no side income loses their main job, it is hard for them to fill in the gap left by it since there are no other substitute for them. If, say everyone, has a side income, it will greatly accelerate