Unless I missed something, you'd need a lot less than 50 years in your scenario, because you'd be investing your monthly $1654. Assuming 6% inflation-adjusted return, you would get a lot of the $1M from your returns. You'd need to do the exact calculation, but a rough order of magnitude calculation would imply less than 25 years. I put together a useful table that shows how long you'd need given a set fraction of income saved and a set fraction of income needed as retirement income: https://medium.com/financial-strategy/how-soon-can-you-reach-your-personal-fire-point-f02172a5710.