i think you're dramatically oversimplifying this, as 1) many people don't make enough money to cover basic expenses let alone invest in stocks and 2) not all employers offer 401k-type plans. plus if you start your own business or something you don't get shit either
There are people living on or bellow the poverty line that are unable to save money.
However the majority of people aren't living under these conditions.
Someone who invests as little as $200 a month can easily see realized gains of up to 300% after 30 years.
Thats $600,000 of tax free income if it was invested in an IRA.
Furthermore while it is ideal to have an employer match your IRA contributions you don't need an employer to start an IRA. There are plenty index funds that will fill this role easily enough.