You don't need a steady income to buy bitcoin. All you need is discretionary funds to be able to invest in bitcoin, yet of course it is much more difficult to determine that you have discretionary funds if you don't have a steady income or if you are not sure from where your next pay is going to come or how your much it is going to be.
This is where it gets a lot of people confused yet, you JayJuanGee has explained it better.
Put differently, steady income is not the base of an investment instead discretionary income is, perhaps guys could have steady income yet it’s not able to fix one’s bills complete for guys to have a discretionary income out of it, hence guys could be earning once in two months yet being able to have a discretionary income so having a steady income in terms of salary doesn’t necessarily means you will be able to have a discretionary income.
Furthermore, however guys earn their income, being able to set out part of the income for expenses (necessary) and after that what ever is left after putting outside emergency funds that will be able to cover 3 to 6 months depending on individual hence discretionary income is what is left and can be used to buy bitcoin, therefore guys will be able to hold for a long term since they have everything set out to cover them for some time hence gambling or trading your holdings wouldn’t be an option.