Older workers are not pushing out younger workers, that is false and goes along with institutionalized age discrimination. There was just a study released showing this is not so. Here an article with links to the actual study.

You are also ignoring something called experience and training that the older worker probably has but bottom line, these age groups are not substitutes of each other.

Worker substitution is an interesting topic. It seems to go with attitudes. In other words, some will claim older workers are perfect substitutes for younger ones, yet, magically foreign workers are not substitutes for native workers.

By occupational categories, even unskilled labor, it's questionable that younger workers are substitutes for older workers. Older workers, even in unskilled jobs, tend to gravitate towards office, retail sales, sorts of positions which require less manual labor, or reasonable manual labor. Teenagers often look for part-time, summer jobs. It looks more suspect that teenagers have been displaced by foreign workers than anything else. Case in point, some of the occupations listed for H-2B Visas are traditional teenager summer jobs. There is a claim of a shortage in lifeguards, waitresses, waiters, cleaning staff, summer resort staff, fast food workers and hence employers claim they need foreign guest workers Visas to bring in workers (H-2B). That isn't even touching upon illegal workers who also can be found heavily in landscaping, construction summer jobs, restaurants, cleaning crews which also are commonly summer as well as part-time jobs.

In 2000, the China PNTR came into play as well as telecommunications, Internet became cheap enough they could offshore outsource jobs. So, two things happened, well, three, they offshore outsourced jobs, foreign guest worker visas were increased and the China trade agreement is so poorly written it encouraged goods manufacturers to move to China in droves and it was almost impossible to compete at that time if they did not. So, it is also possible that career workers, ages 25-65, who normally would be in more semi-skilled, or skilled manufacturing types of jobs were forced back into the lower paying retail trade sorts of jobs. This would be all age groups as worker substitution for those between the ages of 16-19, 20-25, not those over the ages of 65.