A lot of people have basically nothing. That's why social security exists. Despite how easy it is to save half a million or more for retirement through lifelong contributions to a broad market index fund in a 401k or IRA, it is still very common for people to not even start saving for retirement until their 50s, and then they do so in such a conservative manner that they end up with $100,000 or less. I know plenty of people who don't even understand the difference between investing and saving. They put their retirement money in a fvcking savings account.
Read even a single book on finance and do what it says and you will be ahead of 70% of people out there. Considering a $15 book can save/earn you tens, even hundreds of thousands of dollars, you'd think more people would be keen on investing in one, but they don't.