I would definitely divide this question into several parts in this topic.
1. At what level of income, per 1 person in your family, it is possible to accumulate savings
2. Is it possible to set aside savings if you have one job and no investments, passive income and other sources of income.
3. How best to store deferred savings
Regarding the first part, I explain - just taking and allocating 1/3 from the amount of income is not mathematically difficult. The question is - how much does this income cover the needs of life? If this money is not enough or "a stretch" is enough to support yourself or your family - what kind of savings can we talk about?
I guess you have never saved 1/3 your monthly income before. As you said, taking and allocating 1/3 from the monthly income is not difficult, so the only question here is whether you can implement it. Ever since I was a single young graduate, I have managed to save at least 1/3 my monthly income, even after I got married. Just because you can’t save much means other people can’t do that either or logically it is wrong ? Same as keeping fit, that you can’t get disciplined to exercise regularly every day and control the intake of calories does not mean other people can not do the difficult task.
Lucky on you it is really not difficult if your salary is enough or possible that you are rich guy already because of your family? because even my self it is difficult due to other expenses on the needs. Life of having a family is really difficult and now that the prices almost increases all it makes us more difficult, but this doesn't mean that i dont save at all, but only if i have extra spare of money and this is not counted as 1/3 of monthly income as my salary is not the same in a month.