[throwthere]

Bogus. You’re assuming they invested all their dollars at the year 0 (peak) price an and sold everything at the 20 year trough. Of course that’s impossible, they invested over their entire careers which included intervals of much lower prices. So much should be obvious by just looking at the sp500 graph of performance over time. There’s no period where dollar cost averaging over twenty years gave a result like you’re saying.