So... The best-case scenario is $75k per year someone might be able to stash away in a retirement account. Let's say someone is able to do it for 50 years - it leads to $3.75m. It is a decent amount for retirement in my opinion, but 1) it is unlikely to optimize it fully to get there, and 2) doesn't really look stratospheric to make a difference in retirement funds ownership categorizations (i.e. 0.1% owns large part of retirement investments).