It is not a wrong idea to keep 50% of our income for our family expenses and the remaining 50% for investments. But currently the bad economic situation is affecting the people of different countries around the world. As a result of which the standard of living of the people has increased along with the demand and increase in their family consumption. Nowadays people have to spend most of what they earn due to high inflation.
Managing investments with 50% of salary will be the most difficult task and can be risky. Whether your income is low or high, your expenses will be determined based on your income. The demand of a person earning $200 a month and the demand of a person earning $2000 will not be the same. As your income increases, so will your expenses. You may think that if a person earning $200 can meet demand with $150 then I will earn $2000 and meet demand with $150 then you are wrong. If your income is $2000, your demand will also increase to $1500. So I think investing with 50% of income is one of the most difficult decisions for both low income and high income individuals. Many times such a decision may force you to sell your investment at a loss.
Your are absolutely correct but in addition I don't really think the percentage of what we use to invest do matter but what matters is capacity, can we be able to handle our expenses after using some percentage for investment. In as much as using a high percentage of our income to invest is good, because of the outcome we are going to get and also save time for accumulation we should know expenses can never be planned all because there will always be an unexpected expenses. just like I said earlier it's not a bad idea to invest with huge amount of our income but capacity matters.