At any rate, it's not $600k, because OP is going to retire in 30 years. Reasonably invested, I think you could get that up to $2.5M or so by then. And presumably OP won't be spending every cent of income over the next 30 years and will continue contributing to that nest egg, even if modestly.

A 4% withdrawal rate is probably safe if the retirement horizon is only 25 years. On $2.5M that's $100k/yr, which is plenty for most places in the world. Yes, inflation complicates things somewhat, but I think OP will still be fine.