Saving money does not mean you have to live below poverty line. It means you have to "live within your means" => "balance in all things". The hardest thing in life is to deal with "change", in this case, "changing your lifestyle". Those who are not used to "live within their means" will absolutely struggle to do so down the line.

Nobody suggest anyone to put away as much money as possible and live miserably. If we go back to the simplify calculation above given the situation where one cannot afford to travel abroad _right now_, investment can help them with that problem! Nobody say not to touch your investment before you retire. You can withdraw occasionally for reasonable splurge.