Because many desire to turn 65 and sit back in a rocking chair for the rest of their lives. Or at least lead lives of leisure, at the expense of future generations. People who are 65+ have much to give to society other than removing themselves from the workforce.
Cash-strapped pensioners: America has a retirement problem, not a saving problem | The Economist
HOUSE Resolution 67, which Donald Trump signed last week, rolls back a rule that the Labor Department finalised late last year, which would have made it easier for cities and counties to run retirement savings plans for citizens who couldn’t get them through work.