Interesting. Retirement is not only a big change socially and professionally (obviously) but from a financial standpoint as well. It is typical that someone who has had an intact working career will earn about 60% of their salary at the end of their career. Even if moving to a lower tax bracket closes some of the gap, many people will have to cut their expenses quite substantially if they have no access to any other income stream or anything they turn into cash. 

The trilemma with age is that in young adulthood one has time, health/stamina but no money. In adulthood on has health and money but no time. As a retiree, one has time and money but no health. Many will only have time these days. The unluckiest won't have that, either.