It isn't even a question that should be asked because it is obvious that everyone wants to make more money. If you are self employed then you are doing all you can to hold on to your business whereas if you are working for a company you are also doing your best to hang on to your job. The best that people could do is hang on to their source of income.
There are many other methods for you to make more money but though it may seem easy it can be quite difficult. You have several options available to you, one is that you could get another job, second you can have small business on the side, and third of course is for you to request for a pay raise.
There are tons of people who have no choice but to work several jobs just to be able to survive. It is really required particularly if you have a huge family to look after. Many really need to make more money and will find all the ways and means to be able to.
Sitting jobs are also another way for you to earn more. You can offer to babysit, house sit and even walk dogs during your weekends. Surely the costs of these jobs aren't so large but if you add up all your free time in a month then you would have totaled a lot of earnings.