I agree with you that bitcoin investment does not guarantee profits in the long run so that one wouldn't put all his hope in his bitcoin investment as the only means of survival in future, because if bitcoin price goes opposite such person, he will regret it and feel disappointed in life. Which is one of the reasons investing with part of our discretionary income is the best and also look for other means to generate income for the future apart from your bitcoin investment.
New investors should see bitcoin as a long-term store of value and invest mainly into bitcoin in order to save their current funds from inflation so that when they're old, they can be happy that they kept the value of their funds in bitcoin. Profits is an additional advantage for investing in bitcoin and one shouldn't invest into bitcoin only for profits because it's not guaranteed even though, history has proven that the price of bitcoin increases overtime due to constant adoption of bitcoin and its limited supply.
It doesn't mean if someone have started his bitcoin investment and could not continue accumulating more, because of some financial challenges. The most important thing is that you shouldn't sell the bitcoin that you have already accumulated but hodli when things are rough with you.
We have talked about many scenarios where an investor should set up an emergency funds because of unforeseen challenges because they will happen or not. Someone that lost his job or is down with a severe ailment will pause his bitcoin accumulation until he gets a job back. At least, he already has some amount of bitcoin in his possession and he is far better than a someone without any bitcoin.
Consistency is very good to build and grow your bitcoin investment with discipline because you have the resources to do so, but that doesn't mean that anyone that cannot be consistent with his bitcoin accumulation shouldn't buy bitcoin when he has a discretionary income, even though he can no longer buy for some period of time due to low pay job. Buying first is a good step towards progress and later, when you have gotten a stable job with discretionary income, you can be consistent and persistent in your bitcoin accumulation overtime.