You are very correct without a sources of income it can't be possible to invest in bitcoin, and not only that if a person is living in paycheck to paycheck it will also be impossible to invest in bitcoin, to invest in bitcoin one need to have sources of income to buy bitcoin consistently with their discretionary, and one also need a sources of income to set up emergency fund, for that is the only wey you can run a smooth bitcoin investment.
If what you said is for the purpose of becoming more fluent in investing in Bitcoin, I also think that it would be very good for everyone to apply to themselves. But for those who live from paycheck to paycheck can also apply it even though they do not have other income to allocate to Bitcoin investment, because as long as someone has the desire to invest in Bitcoin, of course he will try to make it happen in some way without having to go hungry from month to month. For example, when someone starts receiving a salary from his job, he can set aside a little of his salary for investment purposes because Bitcoin can also be purchased in small amounts. This means that everyone who has a desire for it, it is better not to wait and do it as early as possible so that the time he has is not wasted just like that.
Because all of these things depend on the intention and effort of a person, not waiting to have another income first before running an investment in Bitcoin. And you can also change your mindset like that if at this time you still do not have more income and only live from paycheck to paycheck, but if you are trying to get more income for you to use specifically for Bitcoin investment, of course that is very good. However, I suggest you not to waste time waiting for it so that you can also be more hasty in realizing your own investment from now on.