In praise of older workers: Carlos Slim (age 73)

Billionaire Carlos Slim, age 73, says workers--those in developed economies, anyway--are at their prime in their 60s and there is no reason for them to retire. "When you have an industrial economy like in the past where people ... do a lot of physical work and people live less years, it's OK to retire at 65," Slim told CNBC. "(But) When you have a society of knowledge and experience and informa...