Well, well, well ... interesting topic; one of my favorite. If you want to pursue an historical slant to the topic, you might include a comparison of how a high dchool education used to prepare students for life versus how it now prepares students for life. For instance, once, students could leave high school and gain employment in secretarial jobs or in mechanical jobs, etc. Of course, those who could avail themselves of the opportunity were prepared for college educations beyond high school.
In our present society, it is virtually impossible to leave high school and attain employment at any significant level, though it need not be so. For example, a high school in Central Maine has a woodworking and construction program whereby students build a house each year--sell it--and even take commissions on others to build, so that they may graduate high school and enter the job market at a reasonable income and prestige level. If you want to pursue this tack, the aim/purpose sentence of your Introduction might read something like this:
The aim of this examination is to place current trends of preparing students for real life in context with historic trends to better evaluate whether American schools do or do not prepare students for real life.