I do think this is still pretty relevant. I'm not a portfolio theorist, but I believe a lot of modern asset allocation is structured around risk of short-term liquidity. That is why allocation becomes more stock heavy as you have more years until retirement (for retirement accounts).

I think a lot of people would say, "if you gave me 50 years, and a five year window in which to divest, you should definitely go all stock". I don't think that would be absurdly controversial. Looking at this data though, given the risk, it actually isn't a slam dunk.

Now this isn't to say that one shouldn't diversify among equities, but I suspect you'd see similar charts for random selection diversified among mutual funds/indices.