Mandatory retirement can be developed on one of several models. Depending on the prevailing ideology, some ways will be harder to interpret than others. Even after the economy recovers in 2020, there will be some industries that will hire people at a faster rate than other industries.
Jobs will re-emerge in metropolitan areas first, spreading to smaller cities and eventually to small towns and the rural countryside.
The Liberal Model:
Mandatory retirement will essential be restored near the end of the 2020s after a failed experiement in the 2000s by Dalton McGuinty's Ontario provincial government. Even in the future, people will enjoy the life of leisure that comes with old age and realize that working until death is not a good idea (especially in the winter and summer, where their bodies are more sensitive to global warming and polar vortexes).
However, the mandatory retirement age will be boosted up to 75, with an option to collect an unreduced pension starting at 67. Many seniors' complexes will be amazed at the news that seniors will be retiring again instead of facing the "daily grind" until their bodies can't take it anymore.
In Canada, the retirement age has been boosted from 65 to 67; with plans to make 69 the official retirement age a reality by 2024.
The Conservative Model (Thatcher, Reagan, Bill Clinton, George W. Bush)
Also known as neoliberalism or the neoconservative model. Retirement will be a phased out concept and people will continue working until they die. Weekends will be abolished and special needs children will have to work in sweatshops in lieu of special education programs.
This is currently being developed in Australia, where Tony Abbott wishes to make the retirement age 70.
The Ludic/Anti-work model
Retirement is no longer a concept because society has developed to such a technological degree that it no longer needs to work or refuses to work. Therefore capitalism will become a thing of the past by May 2061. A very unlikely scenario seeing as capitalism is used to create world domination and control and an elite class of people who decide where resources are used.
Dennis the Menace, in his depiction in the U.S. comic strips, shows the anti-work ethic that people may openly display in a post-capitalist world.
A transhuman model:
Aging will no longer be a concern or measure of human capacity because the body will be augmented by technology that gives it longevity. Therefore people will work until their bodies are "retired" or "terminated" for other reasons. Hopefully work and drudgery might change as a result of the body being able to handle more load, while possibly being more resistant to boredom.
Most workplace tasks by the year 2050 will be as easy as playing a massive multiplayer online video game like Unreal Tournament or the 2014 version of SimCity.