3% happens to be the rate that stocks have historically appreciated above inflation, so by doing this you'll be a millionaire in today's money.
Don't believe me? Try it: http://www.bankrate.com/calculators/savings/simple-savings-c...
EDIT: For the poor, there are many structural problems that lead to a cycle of poverty, but it is possible to escape even that with very good money management. I dated a girl whose parents came to America on a raft, with a fifth-grade education. They slept outside the 7/11 where they worked at first (didn't have to spend any money on rent), and ended up owning a large portion of their town by the time they were in their 50s.
In short, don't knock thrift. Yes, earning more is always great, but savings combined with compound interest is magical.