Boring way to become a millionaire

With a long enough time frame, very, very smalls sums can become $1 million, thanks to compound interest. However, assuming you don't have, say, 100 years in which to compound your money, below is a hypothetical scenario that could realistically take place:

1. Save up $50,000 by age 27.
2. Invest that $50,000 at a 7.8% annual return for the subsequent 40 years.
3. Spend every cent that you earn from that point on in your working life. Don't bother saving because you don't need to save any more in order to hit your $1 million goal.
4. Retire at age 67 with your $50,000 having grown into just over $1 million.