And that is exactly the situation of everyone that has ever retired and considered or completed OMY, and sometimes many times over.
Whether it is healthcare, kids college expenses, SS, the stock market, higher taxes, lower taxes, having extra for travel, the extra home, etc., there will always be another reason to OMY.
The only certain thing is death. And generally you do not know when it is coming, but you know the older you get, it is very likely closer than the year before.
When you are ready to retire, you retire. When you are not, you work. Work is only an option, no one is required to do it. The only reason a person would do it, is to create more choices in life.