For me, with the expectation that the prices of products and services would continue to rise as well as the value of bitcoin, for a person retiring, who would no longer invest, 15BTC would be enough to leave a comfortable life for about 30years
For someone that wants to leave legacies for the family, 25BTC would go a long way maintaining the comfort of the family for a while after your demise.
That is, about 10BTC would go into investment to yield great fortune for the livelihood of the family
Imagine what will happen once even sats will be scarce - it's going to be a bloodbath there for anything BTC.
And we will be on top due to how we act now, even if we won't gather that much BTC (not much for the retirement, probably).