Yes, people need to seriously think about this, @phil.
The critical part, imho, if to when to switch from accumulation to distribution for regular funds especially.
The dude who came up with 4% safe withdrawal doctrine now says that it is actually 4.7% of 'safe" spending per year.

Basically, in US, if the family has $1mil in ret funds (which should be quite doable if you had 401K and worked for, say, 30-35 years) and $3/k a mo from soc sec ($1550 is average for a person), then such "average" family should have about 47K+37K=84K/year in available funds, which should be enough in most parts of US. NY-maybe 125-150K/year, but in NY most people might have accumulated more because salaries there are higher as well.

Therefore, bitcoin is mostly extra, which could be either given to next gen, to charity or to the extended family.