I do not like the idea of compulsory retirement. If an elderly person wants to work past 65, and if their employer believes they remain physically and mentally capable, then I see no justification for allowing discriminatIon based solely on age.
I think the idea that older workers are somehow “hoarding jobs”, preventing younger workers from advancing, is way overestimated. Most employers already consider older workers to be a drag on productivity, and most are constantly looking for opportunities to replace them with lower paid, younger people.
Let’s also remember the demographic trends. First, we are all living longer. In 1900, US male life expectancy was 47. It is now 79 years, but by the end of the century, we are on pace to reach 100! Second, young people are having fewer kids, and birth rates in most westernized countries has fallen below the replacement rate of 2. If we force decades of mandatory retirement on older workers, then companies will have no choice but to seek productivity improvements either through automation or immigration (neither of which is necessarily great for a younger, potentially under skilled domestic work force).