[edited out]
You are right, as a poor person the process of building one's Bitcoin investment will take more time than expected especially when he has no emergency and other back up funds because he will start building those funds a long side with his or her Bitcoin investment and because his or her discretion income is small building those things together will take a very long time.
One thing that also prolong the journey for a poor man is excessive emergency issues when his having too much emergency issues it will be hard for him to build up except those emergencies are within the means of his discretion income if is not then it will be impossible for him to build up his Bitcoin because those emergencies will eat up all his back ups funds and his Bitcoin.
Part of the goal should be to build up back up cash so that he is not getting into emergency situations, and yeah, you are correct, that a guy with low discretionary income, he will constantly be fighting to figure out how to keep building his back up funds and his bitcoin and there may well be periods in which he is not able to buy bitcoin, and hopefully he can have systems in place so that he does not have to sell his bitcoin also... and yes.. not easy.. and each person has to figure out the extent to which he can even invest into bitcoin.. and if he has enough discretionary income to actually be able to invest in bitcoin.. including that if he is actually misclassifying his funds as discretionary when they are actually needed to be in his back up funds or his emergency funds because he already has cashflow issues that might relate to the amount of cash coming in being too low and/or the amount of his expenses being too high.
For me I will say for a low class earner or a poor person who barely feed his family and struggling to invest in bitcoin due to having several problems surrounding him, he should avoid bitcoin investment and set his financial strength in a balance first before investing in bitcoin. We have surely discussed that bitcoin should be invested comfortablely without having feeling that we are investing since we may have settled all important things including family expenses, setting out emergenct and or backup fund and having reserved fund for weekly investment. But if the situation is critical and is affecting the poor investor, I think he should increase or his build a good financial strength or increase his discretion before embacking in the bitcoin investment journey since its a long time. But if the poor person can be able to squeeze as little as he can for a long time then it's fine.