The fact that you don't have a steady source of income doesn't mean you won't have something that you will be getting money from and as a matter of fact having steady source of income doesn't guarantee long term investment rather long term investment is a matter of what a particular investor want from their investment just like they have been saying before. However, if someone doesn't have steady source of income he or she will device a way that his investment will be so that it doesn't clash or choke them up and there are people who are doing well in this Bitcoin investment without a steady source of income than people with steady source of income because you can still have money everywhere and don't know how to manage your investment.
As you can see the area i highlighted that is where you got it wrong, how can you say that having a steady source of income doesn't guarantee that an investment will last long, are you for real? If an investor do not have a steady flow of income how can he be able to continue making accumulations and build a solid portfolio in the long term?, In fact, i put it to you that having a steady source of income is one of the prerequisites that guarantees long term investment because firstly, you won't tamper with your holdings when you haven't concluded with your accumulation stages, then secondly you will have enough money that you will use to be funding your DCA regularly but if you don't have a steady flow of income you might stagnate your investment processes such that you won't be able to continue accumulating and at some point you will feel like tampering with your holdings to attend to some of your immediate needs and before you know it you might end up using all the money you have invested already so as an investor, having a steady source of income is important because it will help propagate your investment within your accumulation stages.